fix(sqlite): columns with the same name stay separate in query results (#1144)

lib/core/database/sqlite_sql.dart

@@ -268,6 +268,25 @@ class _SqliteSqlScan {
   }
 }
 
+/// [sql] as a `SELECT * FROM (...)` wrapper, so SQLite names every output
+/// column uniquely: `SELECT o.id, u.id` gives `id` and `id:1` instead of two
+/// `id` columns. `rawQuery` returns rows as maps keyed by name, so repeated
+/// names would collapse into one (#1144).
+///
+/// Only a single `SELECT` or `WITH` statement is wrapped. Anything else, and
+/// several statements at once, come back unchanged.
+String sqliteUniqueColumnsSql(String sql) {
+  final stmt = sqliteStripSqlComments(sql).trim().toLowerCase();
+  if (!RegExp(r'^(select|with)\b').hasMatch(stmt)) return sql;
+  if (sqliteHasMultipleStatements(sql)) return sql;
+  var body = sql.trim();
+  while (body.endsWith(';')) {
+    body = body.substring(0, body.length - 1).trimRight();
+  }
+  // The newlines keep a trailing `-- comment` from swallowing the `)`.
+  return 'SELECT * FROM (\n$body\n)';
+}
+
 bool _isIdentStart(int c) => (c >= 0x61 && c <= 0x7a) || c == 0x5f;
 
 bool _isIdentPart(int c) => _isIdentStart(c) || (c >= 0x30 && c <= 0x39);

lib/features/sqlite/sqlite_sql_workspace.dart

@@ -86,8 +86,10 @@ class SqliteSqlExecutionDelegate extends SqlExecutionDelegate {
     }
 
     final cap = limit ?? kDefaultSqlResultMaxRows;
+    // Wrapped first, so the LIMIT lands on the outer query and the columns
+    // keep unique names (#1144).
     final effectiveSql = sqliteSqlIsReadOnlyQuery(sql)
-        ? injectSqlLimit(sql, cap)
+        ? injectSqlLimit(sqliteUniqueColumnsSql(sql), cap)
         : sql;
 
     final results = await conn.executeWithTimeout(effectiveSql, timeout: timeout);

lib/features/sqlite/sqlite_table_view.dart

@@ -2,6 +2,7 @@ import 'dart:async' show unawaited;
 
 import 'package:flutter/material.dart' as material;
 import 'package:querya_desktop/core/database/sqlite_connection.dart';
+import 'package:querya_desktop/core/database/sqlite_sql.dart';
 import 'package:querya_desktop/core/database/sqlite_service.dart';
 import 'package:querya_desktop/core/database/table_mutation_engine.dart';
 import 'package:querya_desktop/core/editor/querya_code_editor.dart';
@@ -178,7 +179,7 @@ class SqliteTableDataDelegate extends TableDataMutationDelegate {
       throw StateError('Not connected');
     }
 
-    final rs = await conn.execute(sql);
+    final rs = await conn.execute(sqliteUniqueColumnsSql(sql));
     final cols = <String>[];
     if (rs.isNotEmpty) {
       cols.addAll(rs.first.keys);

test/core/database/sqlite_unique_columns_test.dart

@@ -0,0 +1,128 @@
+import 'dart:io';
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:querya_desktop/core/database/sqlite_connection.dart';
+import 'package:querya_desktop/core/database/sqlite_service.dart';
+import 'package:querya_desktop/core/database/sqlite_sql.dart';
+import 'package:querya_desktop/core/mcp/mcp_access_store.dart';
+import 'package:querya_desktop/core/mcp/mcp_query_service.dart';
+import 'package:querya_desktop/core/mcp/mcp_sql_delegates.dart';
+import 'package:querya_desktop/core/storage/local_db.dart';
+import 'package:sqflite_common_ffi/sqflite_ffi.dart';
+
+class _All implements McpAccessPolicy {
+  @override
+  Future<bool> canRead(ConnectionRow row) async => true;
+}
+
+void main() {
+  group('sqliteUniqueColumnsSql', () {
+    test('wraps a SELECT so repeated names get suffixes', () {
+      expect(
+        sqliteUniqueColumnsSql('SELECT o.id, u.id FROM o JOIN u ON 1'),
+        'SELECT * FROM (\nSELECT o.id, u.id FROM o JOIN u ON 1\n)',
+      );
+    });
+
+    test('wraps a WITH query, and leaves comments and semicolons outside', () {
+      expect(
+        sqliteUniqueColumnsSql('-- c\nWITH x AS (SELECT 1) SELECT * FROM x;  '),
+        startsWith('SELECT * FROM (\n-- c\nWITH x AS (SELECT 1) SELECT * FROM x\n'),
+      );
+    });
+
+    test('keeps a trailing line comment inside the parentheses', () {
+      final wrapped = sqliteUniqueColumnsSql('SELECT 1, 1 -- note');
+      expect(wrapped.endsWith('\n)'), isTrue);
+    });
+
+    test('leaves non-select statements and several statements unchanged', () {
+      for (final sql in [
+        'PRAGMA table_info(t)',
+        'EXPLAIN QUERY PLAN SELECT 1',
+        'VALUES (1, 1)',
+        'UPDATE t SET a = 1',
+        'SELECT 1; SELECT 2',
+      ]) {
+        expect(sqliteUniqueColumnsSql(sql), sql, reason: sql);
+      }
+    });
+  });
+
+  group('duplicate column names on a real SQLite file (#1144)', () {
+    late Directory dir;
+    late McpQueryService service;
+
+    setUpAll(() async {
+      sqfliteFfiInit();
+      dir = await Directory.systemTemp.createTemp('querya_dup_cols_');
+      final path = '${dir.path}/shop.db';
+      final seed = SqliteConnection(
+          id: 1, name: 'seed', path: path, createIfMissing: true);
+      await seed.connect();
+      await seed.execute(
+          'CREATE TABLE users (id INTEGER PRIMARY KEY, name TEXT NOT NULL)');
+      await seed.execute('CREATE TABLE orders (id INTEGER PRIMARY KEY, '
+          'user_id INTEGER REFERENCES users(id), total REAL)');
+      await seed.execute("INSERT INTO users VALUES (2, 'bob')");
+      await seed.execute('INSERT INTO orders VALUES (12, 2, 9.5)');
+      await seed.disconnect();
+
+      service = McpQueryService(
+        createDelegate: createReadOnlyMcpDelegate,
+        access: _All(),
+        loadConnections: () async => [
+          ConnectionRow(
+            id: 7,
+            type: 'sqlite',
+            name: 'Shop',
+            host: path,
+            createdAt: DateTime.utc(2026).toIso8601String(),
+          ),
+        ],
+      );
+    });
+
+    tearDownAll(() async {
+      await SqliteService.instance.disconnectAll();
+      await dir.delete(recursive: true);
+    });
+
+    test('two id columns come back as two columns with their own values',
+        () async {
+      final r = await service.runQuery(7,
+          'SELECT o.id, u.id FROM orders o JOIN users u ON u.id = o.user_id');
+      expect(r.columns, ['id', 'id:1']);
+      expect(r.rows.single, ['12', '2']);
+    });
+
+    test('SELECT 1, 1 keeps both columns', () async {
+      final r = await service.runQuery(7, 'SELECT 1, 1');
+      expect(r.columns, ['1', '1:1']);
+      expect(r.rows.single, ['1', '1']);
+    });
+
+    test('o.*, u.* returns every column of both tables', () async {
+      final r = await service.runQuery(7,
+          'SELECT o.*, u.* FROM orders o LEFT JOIN users u ON u.id = o.user_id');
+      expect(r.columns, ['id', 'user_id', 'total', 'id:1', 'name']);
+      expect(r.rows.single, ['12', '2', '9.5', '2', 'bob']);
+    });
+
+    test('a WITH query with a repeated name is unchanged in its values',
+        () async {
+      final r = await service.runQuery(7,
+          'WITH x AS (SELECT id FROM users) SELECT x.id, u.id FROM x JOIN users u ON u.id = x.id -- done');
+      expect(r.columns, ['id', 'id:1']);
+      expect(r.rows.single, ['2', '2']);
+    });
+
+    test('results with unique names keep their names and order', () async {
+      final r = await service.runQuery(7, 'SELECT name, id FROM users ORDER BY id');
+      expect(r.columns, ['name', 'id']);
+      expect(r.rows, [
+        ['bob', '2'],
+      ]);
+    });
+  });
+}