docs: document duckdb support

python/ktx-daemon/tests/test_sql_analysis.py

@@ -129,3 +129,27 @@ def test_validate_read_only_sql_reports_parse_errors() -> None:
     assert response.ok is False
     assert response.error is not None
     assert "Invalid expression" in response.error
+
+
+def test_validate_read_only_sql_accepts_duckdb_select() -> None:
+    response = validate_read_only_sql_response(
+        ValidateReadOnlySqlRequest(
+            dialect="duckdb",
+            sql="select * from read_csv_auto('orders.csv') limit 10",
+        )
+    )
+
+    assert response.ok is True
+    assert response.error is None
+
+
+def test_validate_read_only_sql_rejects_duckdb_mutation() -> None:
+    response = validate_read_only_sql_response(
+        ValidateReadOnlySqlRequest(
+            dialect="duckdb",
+            sql="create table copied as select 1",
+        )
+    )
+
+    assert response.ok is False
+    assert response.error

python/ktx-sl/tests/test_generator.py

@@ -715,6 +715,8 @@ class TestGeneratorEdgeCases:
         assert_valid_sql(result.sql)
 
     def test_dialect_duckdb(self):
+        import sqlglot
+
         engine = SemanticEngine(SOURCES_DIR, dialect="duckdb")
         result = engine.query(
             {
@@ -724,6 +726,7 @@ class TestGeneratorEdgeCases:
         )
         assert result.dialect == "duckdb"
         assert result.sql
+        sqlglot.parse_one(result.sql, read="duckdb")
 
     def test_dialect_mysql(self):
         engine = SemanticEngine(SOURCES_DIR, dialect="mysql")