Allow mapping values to user friendly names

apps/webapp/app/components/code/tsql/tsqlCompletion.ts

@@ -321,8 +321,20 @@ function findColumnSchema(
 
 /**
  * Create completions for enum values
+ * Uses user-friendly values from valueMap when available, showing internal value as detail
  */
 function createEnumValueCompletions(columnSchema: ColumnSchema): Completion[] {
+  // Prefer valueMap over allowedValues if available
+  if (columnSchema.valueMap && Object.keys(columnSchema.valueMap).length > 0) {
+    return Object.entries(columnSchema.valueMap).map(([internalValue, userFriendlyValue]) => ({
+      label: `'${userFriendlyValue}'`,
+      type: "enum",
+      detail: `→ ${internalValue}`,
+      boost: 3, // Highest priority for enum values in value context
+    }));
+  }
+
+  // Fall back to allowedValues
   if (!columnSchema.allowedValues || columnSchema.allowedValues.length === 0) {
     return [];
   }

internal-packages/clickhouse/src/client/tsql.ts

@@ -7,7 +7,12 @@
 
 import type { ClickHouseSettings } from "@clickhouse/client";
 import { z } from "zod";
-import { compileTSQL, type TableSchema, type QuerySettings } from "@internal/tsql";
+import {
+  compileTSQL,
+  transformResults,
+  type TableSchema,
+  type QuerySettings,
+} from "@internal/tsql";
 import type { ClickhouseReader } from "./types.js";
 import { QueryError } from "./errors.js";
 
@@ -36,6 +41,13 @@ export interface ExecuteTSQLOptions<TOut extends z.ZodSchema> {
   clickhouseSettings?: ClickHouseSettings;
   /** Optional TSQL query settings (maxRows, timezone, etc.) */
   querySettings?: Partial<QuerySettings>;
+  /**
+   * Whether to transform result values using the schema's valueMap
+   * When enabled, internal ClickHouse values (e.g., 'COMPLETED_SUCCESSFULLY')
+   * are converted to user-friendly display names (e.g., 'Completed')
+   * @default true
+   */
+  transformValues?: boolean;
 }
 
 /**
@@ -67,6 +79,8 @@ export async function executeTSQL<TOut extends z.ZodSchema>(
   reader: ClickhouseReader,
   options: ExecuteTSQLOptions<TOut>
 ): Promise<TSQLQueryResult<z.output<TOut>>> {
+  const shouldTransformValues = options.transformValues ?? true;
+
   try {
     // 1. Compile the TSQL query to ClickHouse SQL
     const { sql, params } = compileTSQL(options.query, {
@@ -86,7 +100,22 @@ export async function executeTSQL<TOut extends z.ZodSchema>(
       settings: options.clickhouseSettings,
     });
 
-    return await queryFn(params);
+    const [error, rows] = await queryFn(params);
+
+    if (error) {
+      return [error, null];
+    }
+
+    // 3. Transform result values if enabled
+    if (shouldTransformValues && rows) {
+      const transformedRows = transformResults(
+        rows as Record<string, unknown>[],
+        options.tableSchema
+      );
+      return [null, transformedRows as z.output<TOut>[]];
+    }
+
+    return [null, rows];
   } catch (error) {
     if (error instanceof Error) {
       return [new QueryError(error.message, { query: options.query }), null];

internal-packages/tsql/src/index.ts

@@ -73,6 +73,11 @@ export {
   validateSortColumn,
   validateGroupColumn,
   column,
+  // Value mapping utilities
+  getUserFriendlyValue,
+  getInternalValue,
+  getAllowedUserValues,
+  isValidUserValue,
 } from "./query/schema.js";
 
 // Re-export printer context
@@ -99,6 +104,13 @@ export {
   type ValidationSeverity,
 } from "./query/validator.js";
 
+// Re-export result transformation utilities
+export {
+  transformResults,
+  createResultTransformer,
+  type TransformResultsOptions,
+} from "./query/results.js";
+
 /**
  * Parse a TSQL SELECT query string into an AST
  *

internal-packages/tsql/src/query/printer.test.ts

@@ -675,6 +675,120 @@ describe("ClickHousePrinter", () => {
   });
 });
 
+describe("Value mapping (valueMap)", () => {
+  /**
+   * Schema with valueMap for status column
+   */
+  const statusMappedSchema: TableSchema = {
+    name: "runs",
+    clickhouseName: "trigger_dev.task_runs_v2",
+    columns: {
+      id: { name: "id", ...column("String") },
+      status: {
+        name: "status",
+        ...column("String"),
+        valueMap: {
+          COMPLETED_SUCCESSFULLY: "Completed",
+          COMPLETED_WITH_ERRORS: "Completed with errors",
+          SYSTEM_FAILURE: "System failure",
+          PENDING: "Pending",
+          EXECUTING: "Running",
+          FAILED: "Failed",
+        },
+      },
+      organization_id: { name: "organization_id", ...column("String") },
+      project_id: { name: "project_id", ...column("String") },
+      environment_id: { name: "environment_id", ...column("String") },
+    },
+    tenantColumns: {
+      organizationId: "organization_id",
+      projectId: "project_id",
+      environmentId: "environment_id",
+    },
+  };
+
+  function createValueMapContext() {
+    const schema = createSchemaRegistry([statusMappedSchema]);
+    return createPrinterContext({
+      organizationId: "org_test",
+      projectId: "proj_test",
+      environmentId: "env_test",
+      schema,
+    });
+  }
+
+  it("should transform user-friendly value to internal value in equality comparison", () => {
+    const ctx = createValueMapContext();
+    const { sql, params } = printQuery("SELECT * FROM runs WHERE status = 'Completed'", ctx);
+
+    // The user-friendly value "Completed" should be transformed to "COMPLETED_SUCCESSFULLY"
+    expect(Object.values(params)).toContain("COMPLETED_SUCCESSFULLY");
+    expect(Object.values(params)).not.toContain("Completed");
+  });
+
+  it("should transform user-friendly values in IN clause", () => {
+    const ctx = createValueMapContext();
+    const { sql, params } = printQuery(
+      "SELECT * FROM runs WHERE status IN ('Completed', 'Failed', 'Running')",
+      ctx
+    );
+
+    // All user-friendly values should be transformed
+    expect(Object.values(params)).toContain("COMPLETED_SUCCESSFULLY");
+    expect(Object.values(params)).toContain("FAILED");
+    expect(Object.values(params)).toContain("EXECUTING");
+    expect(Object.values(params)).not.toContain("Completed");
+    expect(Object.values(params)).not.toContain("Failed");
+    expect(Object.values(params)).not.toContain("Running");
+  });
+
+  it("should handle case-insensitive value matching", () => {
+    const ctx = createValueMapContext();
+    const { params: params1 } = printQuery("SELECT * FROM runs WHERE status = 'completed'", ctx);
+    const { params: params2 } = printQuery("SELECT * FROM runs WHERE status = 'COMPLETED'", ctx);
+    const { params: params3 } = printQuery("SELECT * FROM runs WHERE status = 'Completed'", ctx);
+
+    // All variations should map to the same internal value
+    expect(Object.values(params1)).toContain("COMPLETED_SUCCESSFULLY");
+    expect(Object.values(params2)).toContain("COMPLETED_SUCCESSFULLY");
+    expect(Object.values(params3)).toContain("COMPLETED_SUCCESSFULLY");
+  });
+
+  it("should pass through values without mapping if not in valueMap", () => {
+    const ctx = createValueMapContext();
+    const { params } = printQuery("SELECT * FROM runs WHERE status = 'UNKNOWN_STATUS'", ctx);
+
+    // Value not in valueMap should pass through unchanged
+    expect(Object.values(params)).toContain("UNKNOWN_STATUS");
+  });
+
+  it("should transform values in NOT IN clause", () => {
+    const ctx = createValueMapContext();
+    const { sql, params } = printQuery(
+      "SELECT * FROM runs WHERE status NOT IN ('Pending', 'System failure')",
+      ctx
+    );
+
+    expect(Object.values(params)).toContain("PENDING");
+    expect(Object.values(params)).toContain("SYSTEM_FAILURE");
+  });
+
+  it("should transform values in != comparison", () => {
+    const ctx = createValueMapContext();
+    const { params } = printQuery("SELECT * FROM runs WHERE status != 'Failed'", ctx);
+
+    expect(Object.values(params)).toContain("FAILED");
+  });
+
+  it("should not transform values for columns without valueMap", () => {
+    const ctx = createValueMapContext();
+    const { params } = printQuery("SELECT * FROM runs WHERE id = 'Completed'", ctx);
+
+    // 'id' column has no valueMap, so "Completed" should pass through unchanged
+    expect(Object.values(params)).toContain("Completed");
+  });
+});
+
 describe("Edge cases", () => {
   it("should handle empty string values", () => {
     const { sql, params } = printQuery("SELECT * FROM task_runs WHERE status = ''");

internal-packages/tsql/src/query/printer.ts

@@ -47,7 +47,7 @@ import {
   validateFunctionArgs,
 } from "./functions";
 import { PrinterContext } from "./printer_context";
-import { findTable, validateTable, TableSchema } from "./schema";
+import { findTable, validateTable, TableSchema, ColumnSchema, getInternalValue } from "./schema";
 
 /**
  * Result of printing an AST to ClickHouse SQL
@@ -649,15 +649,21 @@ export class ClickHousePrinter {
   }
 
   private visitCompareOperation(node: CompareOperation): string {
+    // Check if we need to transform values using valueMap
+    const columnSchema = this.extractColumnSchemaFromExpression(node.left);
+
+    // Transform the right side if it contains user-friendly values
+    const transformedRight = this.transformValueMapExpression(node.right, columnSchema);
+
     const left = this.visit(node.left);
-    const right = this.visit(node.right);
+    const right = this.visit(transformedRight);
 
     switch (node.op) {
       case CompareOperationOp.Eq:
         // Handle NULL comparison
         if (
-          (node.right as Constant).expression_type === "constant" &&
-          (node.right as Constant).value === null
+          (transformedRight as Constant).expression_type === "constant" &&
+          (transformedRight as Constant).value === null
         ) {
           return `isNull(${left})`;
         }
@@ -672,8 +678,8 @@ export class ClickHousePrinter {
       case CompareOperationOp.NotEq:
         // Handle NULL comparison
         if (
-          (node.right as Constant).expression_type === "constant" &&
-          (node.right as Constant).value === null
+          (transformedRight as Constant).expression_type === "constant" &&
+          (transformedRight as Constant).value === null
         ) {
           return `isNotNull(${left})`;
         }
@@ -722,6 +728,113 @@ export class ClickHousePrinter {
     }
   }
 
+  /**
+   * Extract column schema from a field expression if it references a known column
+   */
+  private extractColumnSchemaFromExpression(expr: Expression): ColumnSchema | null {
+    if ((expr as Field).expression_type !== "field") return null;
+
+    const field = expr as Field;
+    const chain = field.chain;
+
+    if (chain.length === 0) return null;
+
+    const firstPart = chain[0];
+    if (typeof firstPart !== "string") return null;
+
+    // Qualified reference: table.column
+    if (chain.length >= 2) {
+      const tableAlias = firstPart;
+      const tableSchema = this.tableContexts.get(tableAlias);
+      if (!tableSchema) return null;
+
+      const columnName = chain[1];
+      if (typeof columnName !== "string") return null;
+
+      return tableSchema.columns[columnName] || null;
+    }
+
+    // Unqualified reference
+    const columnName = firstPart;
+    for (const tableSchema of this.tableContexts.values()) {
+      const columnSchema = tableSchema.columns[columnName];
+      if (columnSchema) {
+        return columnSchema;
+      }
+    }
+
+    return null;
+  }
+
+  /**
+   * Transform an expression's values using the column's valueMap if applicable
+   * Returns the original expression if no transformation is needed
+   */
+  private transformValueMapExpression(
+    expr: Expression,
+    columnSchema: ColumnSchema | null
+  ): Expression {
+    // No column schema or no valueMap, return as-is
+    if (!columnSchema || !columnSchema.valueMap) {
+      return expr;
+    }
+
+    // Handle constant string values
+    if ((expr as Constant).expression_type === "constant") {
+      const constant = expr as Constant;
+      if (typeof constant.value === "string") {
+        const internalValue = getInternalValue(columnSchema, constant.value);
+        if (internalValue !== constant.value) {
+          // Return a new constant with the transformed value
+          return {
+            expression_type: "constant",
+            value: internalValue,
+          } as Constant;
+        }
+      }
+      return expr;
+    }
+
+    // Handle arrays (for IN expressions with [...])
+    if ((expr as ASTArray).expression_type === "array") {
+      const array = expr as ASTArray;
+      const transformedExprs = array.exprs.map((e) =>
+        this.transformValueMapExpression(e, columnSchema)
+      );
+
+      // Check if any expressions were actually transformed
+      const hasChanges = transformedExprs.some((e, i) => e !== array.exprs[i]);
+      if (hasChanges) {
+        return {
+          expression_type: "array",
+          exprs: transformedExprs,
+        } as ASTArray;
+      }
+      return expr;
+    }
+
+    // Handle tuples (for IN expressions with (...))
+    if ((expr as Tuple).expression_type === "tuple") {
+      const tuple = expr as Tuple;
+      const transformedExprs = tuple.exprs.map((e) =>
+        this.transformValueMapExpression(e, columnSchema)
+      );
+
+      // Check if any expressions were actually transformed
+      const hasChanges = transformedExprs.some((e, i) => e !== tuple.exprs[i]);
+      if (hasChanges) {
+        return {
+          expression_type: "tuple",
+          exprs: transformedExprs,
+        } as Tuple;
+      }
+      return expr;
+    }
+
+    // Other expression types, return as-is
+    return expr;
+  }
+
   private visitBetweenExpr(node: BetweenExpr): string {
     const expr = this.visit(node.expr);
     const low = this.visit(node.low);

internal-packages/tsql/src/query/results.test.ts

@@ -0,0 +1,234 @@
+import { describe, it, expect } from "vitest";
+import { transformResults, createResultTransformer } from "./results.js";
+import { column, type TableSchema } from "./schema.js";
+
+/**
+ * Test schema with valueMap
+ */
+const taskRunsSchema: TableSchema = {
+  name: "task_runs",
+  clickhouseName: "trigger_dev.task_runs_v2",
+  columns: {
+    id: { name: "id", ...column("String") },
+    status: {
+      name: "status",
+      ...column("String"),
+      valueMap: {
+        COMPLETED_SUCCESSFULLY: "Completed",
+        COMPLETED_WITH_ERRORS: "Completed with errors",
+        SYSTEM_FAILURE: "System failure",
+        PENDING: "Pending",
+        EXECUTING: "Running",
+        FAILED: "Failed",
+        CANCELLED: "Cancelled",
+      },
+    },
+    environment_type: {
+      name: "environment_type",
+      ...column("String"),
+      valueMap: {
+        DEVELOPMENT: "Development",
+        STAGING: "Staging",
+        PRODUCTION: "Production",
+      },
+    },
+    task_identifier: { name: "task_identifier", ...column("String") },
+    organization_id: { name: "organization_id", ...column("String") },
+    project_id: { name: "project_id", ...column("String") },
+    environment_id: { name: "environment_id", ...column("String") },
+  },
+  tenantColumns: {
+    organizationId: "organization_id",
+    projectId: "project_id",
+    environmentId: "environment_id",
+  },
+};
+
+/**
+ * Schema without valueMap
+ */
+const simpleSchema: TableSchema = {
+  name: "simple",
+  clickhouseName: "trigger_dev.simple",
+  columns: {
+    id: { name: "id", ...column("String") },
+    name: { name: "name", ...column("String") },
+    organization_id: { name: "organization_id", ...column("String") },
+    project_id: { name: "project_id", ...column("String") },
+    environment_id: { name: "environment_id", ...column("String") },
+  },
+  tenantColumns: {
+    organizationId: "organization_id",
+    projectId: "project_id",
+    environmentId: "environment_id",
+  },
+};
+
+describe("transformResults", () => {
+  it("should transform internal values to user-friendly values", () => {
+    const rows = [
+      { id: "run_1", status: "COMPLETED_SUCCESSFULLY", task_identifier: "my-task" },
+      { id: "run_2", status: "PENDING", task_identifier: "other-task" },
+      { id: "run_3", status: "FAILED", task_identifier: "my-task" },
+    ];
+
+    const transformed = transformResults(rows, [taskRunsSchema]);
+
+    expect(transformed[0].status).toBe("Completed");
+    expect(transformed[1].status).toBe("Pending");
+    expect(transformed[2].status).toBe("Failed");
+  });
+
+  it("should transform multiple columns with valueMaps", () => {
+    const rows = [
+      { id: "run_1", status: "COMPLETED_SUCCESSFULLY", environment_type: "PRODUCTION" },
+      { id: "run_2", status: "PENDING", environment_type: "DEVELOPMENT" },
+    ];
+
+    const transformed = transformResults(rows, [taskRunsSchema]);
+
+    expect(transformed[0].status).toBe("Completed");
+    expect(transformed[0].environment_type).toBe("Production");
+    expect(transformed[1].status).toBe("Pending");
+    expect(transformed[1].environment_type).toBe("Development");
+  });
+
+  it("should not modify columns without valueMap", () => {
+    const rows = [
+      { id: "run_1", status: "COMPLETED_SUCCESSFULLY", task_identifier: "my-task" },
+    ];
+
+    const transformed = transformResults(rows, [taskRunsSchema]);
+
+    // id and task_identifier should be unchanged
+    expect(transformed[0].id).toBe("run_1");
+    expect(transformed[0].task_identifier).toBe("my-task");
+  });
+
+  it("should pass through values not in valueMap unchanged", () => {
+    const rows = [{ id: "run_1", status: "UNKNOWN_STATUS", task_identifier: "my-task" }];
+
+    const transformed = transformResults(rows, [taskRunsSchema]);
+
+    // UNKNOWN_STATUS is not in the valueMap, should be passed through
+    expect(transformed[0].status).toBe("UNKNOWN_STATUS");
+  });
+
+  it("should return original rows if no columns have valueMap", () => {
+    const rows = [
+      { id: "run_1", name: "test" },
+      { id: "run_2", name: "other" },
+    ];
+
+    const transformed = transformResults(rows, [simpleSchema]);
+
+    // Should return the same array (reference equality)
+    expect(transformed).toBe(rows);
+  });
+
+  it("should handle empty rows array", () => {
+    const rows: Array<{ id: string; status: string }> = [];
+    const transformed = transformResults(rows, [taskRunsSchema]);
+
+    expect(transformed).toEqual([]);
+  });
+
+  it("should handle case-insensitive internal value matching", () => {
+    const rows = [
+      { id: "run_1", status: "completed_successfully" },
+      { id: "run_2", status: "COMPLETED_SUCCESSFULLY" },
+      { id: "run_3", status: "Completed_Successfully" },
+    ];
+
+    const transformed = transformResults(rows, [taskRunsSchema]);
+
+    // All should map to "Completed"
+    expect(transformed[0].status).toBe("Completed");
+    expect(transformed[1].status).toBe("Completed");
+    expect(transformed[2].status).toBe("Completed");
+  });
+
+  it("should preserve non-string column values", () => {
+    const rows = [{ id: "run_1", status: "COMPLETED_SUCCESSFULLY", count: 42, active: true }];
+
+    const transformed = transformResults(rows, [taskRunsSchema]);
+
+    expect(transformed[0].count).toBe(42);
+    expect(transformed[0].active).toBe(true);
+    expect(transformed[0].status).toBe("Completed");
+  });
+
+  it("should preserve row reference if no changes made", () => {
+    const rows = [{ id: "run_1", status: "UNKNOWN_STATUS" }];
+
+    const transformed = transformResults(rows, [taskRunsSchema]);
+
+    // The row has status that doesn't match any valueMap entry
+    // But the column does have a valueMap, so we still check it
+    // Since the value doesn't change, the row reference should be preserved
+    expect(transformed[0]).toBe(rows[0]);
+  });
+
+  it("should handle multiple table schemas", () => {
+    const anotherSchema: TableSchema = {
+      name: "events",
+      clickhouseName: "trigger_dev.events",
+      columns: {
+        id: { name: "id", ...column("String") },
+        event_type: {
+          name: "event_type",
+          ...column("String"),
+          valueMap: {
+            TASK_START: "Started",
+            TASK_END: "Ended",
+          },
+        },
+        organization_id: { name: "organization_id", ...column("String") },
+        project_id: { name: "project_id", ...column("String") },
+        environment_id: { name: "environment_id", ...column("String") },
+      },
+      tenantColumns: {
+        organizationId: "organization_id",
+        projectId: "project_id",
+        environmentId: "environment_id",
+      },
+    };
+
+    const rows = [
+      { status: "COMPLETED_SUCCESSFULLY", event_type: "TASK_START" },
+      { status: "PENDING", event_type: "TASK_END" },
+    ];
+
+    const transformed = transformResults(rows, [taskRunsSchema, anotherSchema]);
+
+    expect(transformed[0].status).toBe("Completed");
+    expect(transformed[0].event_type).toBe("Started");
+    expect(transformed[1].status).toBe("Pending");
+    expect(transformed[1].event_type).toBe("Ended");
+  });
+});
+
+describe("createResultTransformer", () => {
+  it("should create a reusable transformer function", () => {
+    const transform = createResultTransformer([taskRunsSchema]);
+
+    const rows1 = [{ id: "1", status: "COMPLETED_SUCCESSFULLY" }];
+    const rows2 = [{ id: "2", status: "FAILED" }];
+
+    const transformed1 = transform(rows1);
+    const transformed2 = transform(rows2);
+
+    expect(transformed1[0].status).toBe("Completed");
+    expect(transformed2[0].status).toBe("Failed");
+  });
+
+  it("should return original rows if no valueMap columns exist", () => {
+    const transform = createResultTransformer([simpleSchema]);
+
+    const rows = [{ id: "1", name: "test" }];
+    const transformed = transform(rows);
+
+    expect(transformed).toBe(rows);
+  });
+});
+

internal-packages/tsql/src/query/results.ts

@@ -0,0 +1,153 @@
+/**
+ * Result transformation utilities for TSQL queries
+ *
+ * Transforms query result values from internal ClickHouse values
+ * to user-friendly display names using the column valueMap.
+ */
+
+import type { TableSchema, ColumnSchema } from "./schema.js";
+import { getUserFriendlyValue } from "./schema.js";
+
+/**
+ * Options for transforming query results
+ */
+export interface TransformResultsOptions {
+  /**
+   * If true, transform values even if the column was aliased (e.g., SELECT status AS s)
+   * Default: false (aliased columns are not transformed since the user explicitly chose a different name)
+   */
+  transformAliased?: boolean;
+}
+
+/**
+ * Transform query result rows, mapping internal values to user-friendly display names
+ *
+ * This function iterates over result rows and transforms any column values that have
+ * a `valueMap` defined in their schema, converting internal ClickHouse values
+ * (e.g., 'COMPLETED_SUCCESSFULLY') back to user-friendly display names (e.g., 'Completed').
+ *
+ * @param rows - Array of result rows to transform
+ * @param schema - Array of table schemas containing column definitions with valueMaps
+ * @param options - Optional transformation options
+ * @returns New array of rows with transformed values
+ *
+ * @example
+ * ```typescript
+ * const schema: TableSchema[] = [{
+ *   name: "task_runs",
+ *   clickhouseName: "trigger_dev.task_runs_v2",
+ *   columns: {
+ *     status: {
+ *       name: "status",
+ *       type: "String",
+ *       valueMap: {
+ *         "COMPLETED_SUCCESSFULLY": "Completed",
+ *         "PENDING": "Pending",
+ *       },
+ *     },
+ *   },
+ *   tenantColumns: { organizationId: "organization_id", projectId: "project_id", environmentId: "environment_id" },
+ * }];
+ *
+ * const results = [{ status: "COMPLETED_SUCCESSFULLY", run_id: "run_123" }];
+ * const transformed = transformResults(results, schema);
+ * // transformed = [{ status: "Completed", run_id: "run_123" }]
+ * ```
+ */
+export function transformResults<T extends Record<string, unknown>>(
+  rows: T[],
+  schema: TableSchema[],
+  options: TransformResultsOptions = {}
+): T[] {
+  // Build a map of column names to their schemas (for columns that have valueMaps)
+  const columnValueMaps = buildColumnValueMaps(schema);
+
+  // If no columns have valueMaps, return the original rows unchanged
+  if (columnValueMaps.size === 0) {
+    return rows;
+  }
+
+  // Transform each row
+  return rows.map((row) => transformRow(row, columnValueMaps));
+}
+
+/**
+ * Build a map of column names to their schemas for columns that have valueMaps
+ */
+function buildColumnValueMaps(schema: TableSchema[]): Map<string, ColumnSchema> {
+  const columnMaps = new Map<string, ColumnSchema>();
+
+  for (const table of schema) {
+    for (const [columnName, columnSchema] of Object.entries(table.columns)) {
+      if (columnSchema.valueMap && Object.keys(columnSchema.valueMap).length > 0) {
+        // Use the TSQL-exposed column name (not the ClickHouse name)
+        columnMaps.set(columnName, columnSchema);
+      }
+    }
+  }
+
+  return columnMaps;
+}
+
+/**
+ * Transform a single row's values using the column valueMaps
+ */
+function transformRow<T extends Record<string, unknown>>(
+  row: T,
+  columnValueMaps: Map<string, ColumnSchema>
+): T {
+  const transformedRow: Record<string, unknown> = {};
+  let hasChanges = false;
+
+  for (const [key, value] of Object.entries(row)) {
+    const columnSchema = columnValueMaps.get(key);
+
+    if (columnSchema && typeof value === "string") {
+      const transformedValue = getUserFriendlyValue(columnSchema, value);
+      transformedRow[key] = transformedValue;
+      if (transformedValue !== value) {
+        hasChanges = true;
+      }
+    } else {
+      transformedRow[key] = value;
+    }
+  }
+
+  // Return original row if no changes were made (preserves reference equality)
+  return hasChanges ? (transformedRow as T) : row;
+}
+
+/**
+ * Create a result transformer bound to a specific schema
+ *
+ * Useful when you need to transform multiple result sets with the same schema.
+ *
+ * @param schema - Array of table schemas
+ * @param options - Optional transformation options
+ * @returns A function that transforms result rows
+ *
+ * @example
+ * ```typescript
+ * const transform = createResultTransformer(schema);
+ *
+ * const results1 = await query1();
+ * const transformed1 = transform(results1);
+ *
+ * const results2 = await query2();
+ * const transformed2 = transform(results2);
+ * ```
+ */
+export function createResultTransformer(
+  schema: TableSchema[],
+  options: TransformResultsOptions = {}
+): <T extends Record<string, unknown>>(rows: T[]) => T[] {
+  const columnValueMaps = buildColumnValueMaps(schema);
+
+  return <T extends Record<string, unknown>>(rows: T[]): T[] => {
+    if (columnValueMaps.size === 0) {
+      return rows;
+    }
+    return rows.map((row) => transformRow(row, columnValueMaps));
+  };
+}
+

internal-packages/tsql/src/query/schema.test.ts

@@ -0,0 +1,168 @@
+import { describe, it, expect } from "vitest";
+import {
+  column,
+  getUserFriendlyValue,
+  getInternalValue,
+  getAllowedUserValues,
+  isValidUserValue,
+  type ColumnSchema,
+} from "./schema.js";
+
+describe("Value mapping helper functions", () => {
+  const columnWithValueMap: ColumnSchema = {
+    name: "status",
+    ...column("String"),
+    valueMap: {
+      COMPLETED_SUCCESSFULLY: "Completed",
+      COMPLETED_WITH_ERRORS: "Completed with errors",
+      SYSTEM_FAILURE: "System failure",
+      PENDING: "Pending",
+      EXECUTING: "Running",
+      FAILED: "Failed",
+    },
+  };
+
+  const columnWithAllowedValues: ColumnSchema = {
+    name: "status",
+    ...column("String"),
+    allowedValues: ["completed", "pending", "failed"],
+  };
+
+  const columnWithNoRestrictions: ColumnSchema = {
+    name: "task_identifier",
+    ...column("String"),
+  };
+
+  describe("getUserFriendlyValue", () => {
+    it("should return user-friendly value for internal value", () => {
+      expect(getUserFriendlyValue(columnWithValueMap, "COMPLETED_SUCCESSFULLY")).toBe("Completed");
+      expect(getUserFriendlyValue(columnWithValueMap, "PENDING")).toBe("Pending");
+      expect(getUserFriendlyValue(columnWithValueMap, "EXECUTING")).toBe("Running");
+    });
+
+    it("should be case-insensitive for internal value lookup", () => {
+      expect(getUserFriendlyValue(columnWithValueMap, "completed_successfully")).toBe("Completed");
+      expect(getUserFriendlyValue(columnWithValueMap, "Completed_Successfully")).toBe("Completed");
+      expect(getUserFriendlyValue(columnWithValueMap, "COMPLETED_SUCCESSFULLY")).toBe("Completed");
+    });
+
+    it("should return original value if no mapping exists", () => {
+      expect(getUserFriendlyValue(columnWithValueMap, "UNKNOWN_STATUS")).toBe("UNKNOWN_STATUS");
+    });
+
+    it("should return original value if column has no valueMap", () => {
+      expect(getUserFriendlyValue(columnWithNoRestrictions, "any_value")).toBe("any_value");
+    });
+  });
+
+  describe("getInternalValue", () => {
+    it("should return internal value for user-friendly value", () => {
+      expect(getInternalValue(columnWithValueMap, "Completed")).toBe("COMPLETED_SUCCESSFULLY");
+      expect(getInternalValue(columnWithValueMap, "Pending")).toBe("PENDING");
+      expect(getInternalValue(columnWithValueMap, "Running")).toBe("EXECUTING");
+    });
+
+    it("should be case-insensitive for user-friendly value lookup", () => {
+      expect(getInternalValue(columnWithValueMap, "completed")).toBe("COMPLETED_SUCCESSFULLY");
+      expect(getInternalValue(columnWithValueMap, "COMPLETED")).toBe("COMPLETED_SUCCESSFULLY");
+      expect(getInternalValue(columnWithValueMap, "Completed")).toBe("COMPLETED_SUCCESSFULLY");
+    });
+
+    it("should return original value if no mapping exists", () => {
+      expect(getInternalValue(columnWithValueMap, "Unknown")).toBe("Unknown");
+    });
+
+    it("should return original value if column has no valueMap", () => {
+      expect(getInternalValue(columnWithNoRestrictions, "any_value")).toBe("any_value");
+    });
+
+    it("should handle multi-word user-friendly values", () => {
+      expect(getInternalValue(columnWithValueMap, "Completed with errors")).toBe(
+        "COMPLETED_WITH_ERRORS"
+      );
+      expect(getInternalValue(columnWithValueMap, "completed with errors")).toBe(
+        "COMPLETED_WITH_ERRORS"
+      );
+      expect(getInternalValue(columnWithValueMap, "System failure")).toBe("SYSTEM_FAILURE");
+    });
+  });
+
+  describe("getAllowedUserValues", () => {
+    it("should return user-friendly values from valueMap", () => {
+      const values = getAllowedUserValues(columnWithValueMap);
+
+      expect(values).toContain("Completed");
+      expect(values).toContain("Pending");
+      expect(values).toContain("Running");
+      expect(values).toContain("Failed");
+      expect(values).toContain("Completed with errors");
+      expect(values).toContain("System failure");
+      expect(values).toHaveLength(6);
+    });
+
+    it("should return allowedValues if no valueMap exists", () => {
+      const values = getAllowedUserValues(columnWithAllowedValues);
+
+      expect(values).toEqual(["completed", "pending", "failed"]);
+    });
+
+    it("should prefer valueMap over allowedValues", () => {
+      const columnWithBoth: ColumnSchema = {
+        name: "status",
+        ...column("String"),
+        allowedValues: ["internal1", "internal2"],
+        valueMap: {
+          internal1: "User 1",
+          internal2: "User 2",
+        },
+      };
+
+      const values = getAllowedUserValues(columnWithBoth);
+
+      expect(values).toEqual(["User 1", "User 2"]);
+    });
+
+    it("should return empty array for column with no restrictions", () => {
+      const values = getAllowedUserValues(columnWithNoRestrictions);
+
+      expect(values).toEqual([]);
+    });
+  });
+
+  describe("isValidUserValue", () => {
+    it("should return true for valid user-friendly values", () => {
+      expect(isValidUserValue(columnWithValueMap, "Completed")).toBe(true);
+      expect(isValidUserValue(columnWithValueMap, "Pending")).toBe(true);
+      expect(isValidUserValue(columnWithValueMap, "Running")).toBe(true);
+    });
+
+    it("should be case-insensitive", () => {
+      expect(isValidUserValue(columnWithValueMap, "completed")).toBe(true);
+      expect(isValidUserValue(columnWithValueMap, "COMPLETED")).toBe(true);
+      expect(isValidUserValue(columnWithValueMap, "running")).toBe(true);
+    });
+
+    it("should return false for invalid values", () => {
+      expect(isValidUserValue(columnWithValueMap, "Unknown")).toBe(false);
+      expect(isValidUserValue(columnWithValueMap, "COMPLETED_SUCCESSFULLY")).toBe(false); // internal value, not user-friendly
+    });
+
+    it("should return true for any value if column has no restrictions", () => {
+      expect(isValidUserValue(columnWithNoRestrictions, "any_value")).toBe(true);
+      expect(isValidUserValue(columnWithNoRestrictions, "another")).toBe(true);
+    });
+
+    it("should validate against allowedValues if no valueMap", () => {
+      expect(isValidUserValue(columnWithAllowedValues, "completed")).toBe(true);
+      expect(isValidUserValue(columnWithAllowedValues, "COMPLETED")).toBe(true);
+      expect(isValidUserValue(columnWithAllowedValues, "unknown")).toBe(false);
+    });
+
+    it("should handle multi-word values", () => {
+      expect(isValidUserValue(columnWithValueMap, "Completed with errors")).toBe(true);
+      expect(isValidUserValue(columnWithValueMap, "completed with errors")).toBe(true);
+      expect(isValidUserValue(columnWithValueMap, "System failure")).toBe(true);
+    });
+  });
+});
+

internal-packages/tsql/src/query/schema.ts

@@ -68,6 +68,15 @@ export interface ColumnSchema {
   description?: string;
   /** Allowed values for this column (for enum-like columns) */
   allowedValues?: string[];
+  /**
+   * Map of internal values to user-friendly display names (for enum-like columns)
+   * Key: internal ClickHouse value (e.g., "COMPLETED_SUCCESSFULLY")
+   * Value: user-friendly display name (e.g., "Completed")
+   *
+   * When set, users can write queries using the user-friendly names,
+   * and results will display user-friendly names instead of internal values.
+   */
+  valueMap?: Record<string, string>;
 }
 
 /**
@@ -274,6 +283,91 @@ export function getClickHouseColumnName(col: ColumnSchema): string {
   return col.clickhouseName ?? col.name;
 }
 
+/**
+ * Get the user-friendly display value for an internal value (case-insensitive)
+ * Used for transforming query results back to user-friendly format
+ *
+ * @param col - The column schema
+ * @param internalValue - The internal ClickHouse value
+ * @returns The user-friendly display value, or the original value if no mapping exists
+ */
+export function getUserFriendlyValue(col: ColumnSchema, internalValue: string): string {
+  if (!col.valueMap) {
+    return internalValue;
+  }
+
+  // Direct lookup first (case-sensitive for exact match)
+  if (col.valueMap[internalValue] !== undefined) {
+    return col.valueMap[internalValue];
+  }
+
+  // Case-insensitive fallback
+  const lowerValue = internalValue.toLowerCase();
+  for (const [internal, friendly] of Object.entries(col.valueMap)) {
+    if (internal.toLowerCase() === lowerValue) {
+      return friendly;
+    }
+  }
+
+  return internalValue;
+}
+
+/**
+ * Get the internal ClickHouse value for a user-friendly value (case-insensitive)
+ * Used for transforming user queries to internal format
+ *
+ * @param col - The column schema
+ * @param userValue - The user-friendly display value
+ * @returns The internal ClickHouse value, or the original value if no mapping exists
+ */
+export function getInternalValue(col: ColumnSchema, userValue: string): string {
+  if (!col.valueMap) {
+    return userValue;
+  }
+
+  const lowerUserValue = userValue.toLowerCase();
+
+  // Search for matching user-friendly value (case-insensitive)
+  for (const [internal, friendly] of Object.entries(col.valueMap)) {
+    if (friendly.toLowerCase() === lowerUserValue) {
+      return internal;
+    }
+  }
+
+  return userValue;
+}
+
+/**
+ * Get all allowed user-friendly values for a column
+ * Used for validation and autocomplete
+ *
+ * @param col - The column schema
+ * @returns Array of allowed user-friendly values, or allowedValues if no valueMap exists
+ */
+export function getAllowedUserValues(col: ColumnSchema): string[] {
+  if (col.valueMap) {
+    return Object.values(col.valueMap);
+  }
+  return col.allowedValues ?? [];
+}
+
+/**
+ * Check if a user-provided value is valid for a column (case-insensitive)
+ *
+ * @param col - The column schema
+ * @param userValue - The user-provided value to validate
+ * @returns true if the value is valid, false otherwise
+ */
+export function isValidUserValue(col: ColumnSchema, userValue: string): boolean {
+  const allowedValues = getAllowedUserValues(col);
+  if (allowedValues.length === 0) {
+    return true; // No restrictions
+  }
+
+  const lowerUserValue = userValue.toLowerCase();
+  return allowedValues.some((v) => v.toLowerCase() === lowerUserValue);
+}
+
 /**
  * Get all column names available for autocomplete
  */

internal-packages/tsql/src/query/validator.ts

@@ -19,6 +19,7 @@ import type {
   Array as ASTArray,
 } from "./ast.js";
 import type { TableSchema, ColumnSchema } from "./schema.js";
+import { getAllowedUserValues, isValidUserValue } from "./schema.js";
 import { CompareOperationOp } from "./ast.js";
 
 /**
@@ -360,8 +361,9 @@ function validateCompareOperation(op: CompareOperation, context: ValidationConte
 
   const { columnSchema, columnName, tableName } = columnInfo;
 
-  // Only validate if the column has allowedValues
-  if (!columnSchema.allowedValues || columnSchema.allowedValues.length === 0) return;
+  // Only validate if the column has allowedValues or valueMap
+  const allowedValues = getAllowedUserValues(columnSchema);
+  if (allowedValues.length === 0) return;
 
   // Check the comparison type
   switch (op.op) {
@@ -432,6 +434,7 @@ function extractColumnFromExpression(
 
 /**
  * Validate that a value matches the allowed enum values for a column
+ * Supports both allowedValues and valueMap, with case-insensitive matching
  */
 function validateEnumValue(
   expr: Expression,
@@ -446,10 +449,12 @@ function validateEnumValue(
   if (typeof constant.value !== "string") return;
 
   const value = constant.value;
-  const allowedValues = columnSchema.allowedValues!;
 
-  if (!allowedValues.includes(value)) {
+  // Use isValidUserValue for case-insensitive validation against user-friendly values
+  if (!isValidUserValue(columnSchema, value)) {
     const columnRef = tableName ? `${tableName}.${columnName}` : columnName;
+    // Show user-friendly values in the error message
+    const allowedValues = getAllowedUserValues(columnSchema);
     context.issues.push({
       message: `Invalid value "${value}" for column "${columnRef}". Allowed values: ${allowedValues.join(
         ", "