fix(grid): show comments for joined query results

apps/desktop/src/components/grid/DataGrid.vue

@@ -71,7 +71,7 @@ import DataGridTextFilterWorkbench from "@/components/grid/DataGridTextFilterWor
 import TemporalCellEditor from "@/components/grid/TemporalCellEditor.vue";
 import EnumCellEditor from "@/components/grid/EnumCellEditor.vue";
 import DataGridReadonlyTextSelection from "@/components/grid/DataGridReadonlyTextSelection.vue";
-import type { QueryResult, ColumnInfo, DatabaseType, ForeignKeyInfo, IndexInfo, TriggerInfo, TableInfoTab } from "@/types/database";
+import type { QueryResult, ColumnInfo, DatabaseType, ForeignKeyInfo, IndexInfo, TriggerInfo, TableInfoTab, QueryResultSourceColumnRef } from "@/types/database";
 import { isQueryExecutionErrorResult } from "@/lib/query/queryResultError";
 import { tableObjectSourceKind } from "@/lib/table/tableObjectSourceKind";
 import { tableColumnDefaultDisplayValue } from "@/lib/table/tableColumnDefaultPresentation";
@@ -346,6 +346,22 @@ interface DataGridProps {
   context?: "results" | "table-data";
   autoTransposeSingleRow?: boolean;
   sourceColumns?: Array<string | undefined>;
+  /**
+   * Column comments for a multi-source query result (e.g. JOIN), indexed by
+   * result-column ordinal (projection order). Populated even when the result is
+   * not editable, so joined results still show comments. `undefined` for a
+   * column that cannot be resolved back to exactly one base column (ambiguous
+   * or computed) — the grid shows no comment instead of a wrong one.
+   */
+  resultColumnComments?: Array<string | undefined>;
+  /**
+   * Display-only result-column -> source mapping for multi-source results,
+   * indexed by result-column ordinal; each entry carries the source identity
+   * (sourceKey + canonical source column name). Used to resolve column
+   * comments per source instead of first-source-wins; never used for row
+   * identity or editing.
+   */
+  queryDisplaySourceColumns?: Array<QueryResultSourceColumnRef | undefined>;
   initialWhereInput?: string;
   initialOrderByInput?: string;
   sortColumn?: string;
@@ -586,6 +602,11 @@ const readonlyTextCell = ref<{
 } | null>(null);
 
 function resolvedColumnComment(column: string, actualColIdx: number): string | undefined {
+  // Multi-source results resolve comments per result ordinal; ambiguous or
+  // unresolved columns yield undefined instead of falling back to a
+  // first-source-wins name map.
+  const ordinalComments = props.resultColumnComments;
+  if (ordinalComments) return ordinalComments[actualColIdx];
   return dataGridColumnCommentFor(columnCommentMap.value, column, props.sourceColumns?.[actualColIdx]);
 }
 
@@ -2116,7 +2137,13 @@ const allColumnTypes = computed(() =>
 const visibleColumnTypes = computed(() => visibleColumnIndexes.value.map((index) => allColumnTypes.value[index]));
 const allColumnTypeVisualKinds = computed(() => allColumnTypes.value.map((type) => resolveDataGridTypeVisualKind(type, resolvedDatabaseType.value)));
 const visibleColumnTypeVisualKinds = computed(() => visibleColumnIndexes.value.map((index) => allColumnTypeVisualKinds.value[index] ?? "unknown"));
-const visibleColumnComments = computed(() => visibleColumnIndexes.value.map((index) => dataGridColumnCommentFor(columnCommentMap.value, props.result.columns[index] ?? "", props.sourceColumns?.[index])));
+const visibleColumnComments = computed(() =>
+  visibleColumnIndexes.value.map((index) => {
+    const ordinalComments = props.resultColumnComments;
+    if (ordinalComments) return ordinalComments[index];
+    return dataGridColumnCommentFor(columnCommentMap.value, props.result.columns[index] ?? "", props.sourceColumns?.[index]);
+  }),
+);
 const visibleColumnCount = computed(() => visibleColumnIndexes.value.length);
 
 const numericColumnRightAlign = computed(() => (settingsStore.editorSettings.numericColumnRightAlign ?? true) && !showTranspose.value);

apps/desktop/src/components/grid/__tests__/DataGridColumnComments.spec.ts

@@ -4,8 +4,10 @@ import { describe, expect, it } from "vitest";
 const dataGridSource = readFileSync(new URL("../DataGrid.vue", import.meta.url), "utf8");
 
 describe("DataGrid column comments", () => {
-  it("uses source column metadata for both inline and tooltip header comments", () => {
-    expect(dataGridSource).toMatch(/function resolvedColumnComment\(column: string, actualColIdx: number\)[\s\S]*?dataGridColumnCommentFor\([\s\S]*?props\.sourceColumns\?\.\[actualColIdx\][\s\S]*?\);\s*\}/);
+  it("uses per-ordinal multi-source comments, falling back to source metadata for single-source grids", () => {
+    expect(dataGridSource).toMatch(
+      /function resolvedColumnComment\(column: string, actualColIdx: number\)[\s\S]*?const ordinalComments = props\.resultColumnComments;[\s\S]*?if \(ordinalComments\) return ordinalComments\[actualColIdx\];[\s\S]*?dataGridColumnCommentFor\([\s\S]*?props\.sourceColumns\?\.\[actualColIdx\][\s\S]*?\);\s*\}/,
+    );
     expect(dataGridSource).toContain(':column-comment="headerColumnComment(col.name, col.actualColIdx)"');
     expect(dataGridSource).toContain(':tooltip-column-comment="resolvedColumnComment(col.name, col.actualColIdx)"');
     expect(dataGridSource).toContain("(column, index) => headerColumnComment(column, index)");

apps/desktop/src/components/layout/ContentArea.vue

@@ -1568,6 +1568,8 @@ defineExpose({ focusSearch, refreshData, refreshQueryEditorCompletionCache, hand
                 :loading="activeTab.isExecuting"
                 :editable="!!activeTab.queryAnalysis || !!mongoQueryResultSaveHandler"
                 :source-columns="activeTab.querySourceColumns"
+                :result-column-comments="activeTab.resultColumnComments"
+                :query-display-source-columns="activeTab.queryDisplaySourceColumns"
                 :custom-save-handler="mongoQueryResultSaveHandler"
                 :mongo-update-target="mongoQueryResultSaveHandler && activeTab.result.mongo_copy_documents?.length === activeTab.result.rows.length ? activeTab.mongoEditTarget : undefined"
                 :query-editability-reason="activeTab.queryEditabilityReason"