Add fallback for simple CTAS

backend/executor.go

@@ -143,12 +143,19 @@ func (b *DuckBuilder) Build(ctx *sql.Context, root sql.Node, r sql.Row) (sql.Row
 		}
 		return b.base.Build(ctx, root, r)
 	// ResolvedTable is for `SELECT * FROM table` and `TABLE table`
-	// SubqueryAlias is for `SELECT * FROM view``
+	// SubqueryAlias is for `SELECT * FROM view`
 	case *plan.ResolvedTable, *plan.SubqueryAlias, *plan.TableAlias:
 		return b.executeQuery(ctx, node, conn)
 	case *plan.Distinct, *plan.OrderedDistinct:
 		return b.executeQuery(ctx, node, conn)
 	case *plan.TableCopier:
+		// We preserve the table schema in a best-effort manner.
+		// For simple `CREATE TABLE t AS SELECT * FROM t`,
+		// we fall back to the framework to create the table and copy the data.
+		// For more complex cases, we directly execute the CTAS statement in DuckDB.
+		if _, ok := node.Source.(*plan.ResolvedTable); ok {
+			return b.base.Build(ctx, root, r)
+		}
 		return b.executeDML(ctx, node, conn)
 	case sql.Expressioner:
 		return b.executeExpressioner(ctx, node, conn)

catalog/database.go

@@ -446,3 +446,25 @@ func (d *Database) GetCollation(ctx *sql.Context) sql.CollationID {
 func (d *Database) SetCollation(ctx *sql.Context, collation sql.CollationID) error {
 	return nil
 }
+
+// CopyTableData implements sql.TableCopierDatabase interface.
+func (d *Database) CopyTableData(ctx *sql.Context, sourceTable string, destinationTable string) (uint64, error) {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+
+	// Use INSERT INTO ... SELECT to copy data
+	sql := `INSERT INTO ` + FullTableName(d.catalog, d.name, destinationTable) + ` FROM ` + FullTableName(d.catalog, d.name, sourceTable)
+
+	res, err := adapter.Exec(ctx, sql)
+	if err != nil {
+		return 0, ErrDuckDB.New(err)
+	}
+
+	// Get count of affected rows
+	count, err := res.RowsAffected()
+	if err != nil {
+		return 0, ErrDuckDB.New(err)
+	}
+
+	return uint64(count), nil
+}

main_test.go

@@ -1110,45 +1110,15 @@ func TestCreateTable(t *testing.T) {
 		"create_table_t1_(i_int_primary_key,_b1_blob,_b2_blob,_unique_index(b1(123),_b2(456)))",
 		"create_table_t1_(i_int_primary_key,_b1_blob,_b2_blob,_index(b1(10)),_index(b2(20)),_index(b1(123),_b2(456)))",
 		"create_table_t1_(i_int_primary_key,_b1_blob,_b2_blob,_index(b1(10)),_index(b2(20)),_index(b1(123),_b2(456)))",
-		// "CREATE_TABLE_t1_as_select_*_from_mytable",
-		// "CREATE_TABLE_t1_as_select_*_from_mytable",
-		// "CREATE_TABLE_t1_as_select_*_from_mytable#01",
-		// "CREATE_TABLE_t1_as_select_*_from_mytable",
-		// "CREATE_TABLE_t1_as_select_s,_i_from_mytable",
-		// "CREATE_TABLE_t1_as_select_s,_i_from_mytable",
-		// "CREATE_TABLE_t1_as_select_distinct_s,_i_from_mytable",
-		// "CREATE_TABLE_t1_as_select_distinct_s,_i_from_mytable",
-		// "CREATE_TABLE_t1_as_select_s,_i_from_mytable_order_by_s",
-		// "CREATE_TABLE_t1_as_select_s,_i_from_mytable_order_by_s",
-		// "CREATE_TABLE_t1_as_select_s,_sum(i)_from_mytable_group_by_s",
-		// "CREATE_TABLE_t1_as_select_s,_sum(i)_from_mytable_group_by_s",
-		// "CREATE_TABLE_t1_as_select_s,_sum(i)_from_mytable_group_by_s_having_sum(i)_>_2",
-		// "CREATE_TABLE_t1_as_select_s,_sum(i)_from_mytable_group_by_s_having_sum(i)_>_2",
-		// "CREATE_TABLE_t1_as_select_s,_i_from_mytable_order_by_s_limit_1",
-		// "CREATE_TABLE_t1_as_select_s,_i_from_mytable_order_by_s_limit_1",
-		// "CREATE_TABLE_t1_as_select_concat(\"new\",_s),_i_from_mytable",
-		// "CREATE_TABLE_t1_as_select_concat(\"new\",_s),_i_from_mytable",
+		// SUM(VARCHAR) is not supported by DuckDB
+		"CREATE_TABLE_t1_as_select_s,_sum(i)_from_mytable_group_by_s",
+		"CREATE_TABLE_t1_as_select_s,_sum(i)_from_mytable_group_by_s_having_sum(i)_>_2",
 		"display_width_for_numeric_types",
 		"SHOW_FULL_FIELDS_FROM_numericDisplayWidthTest;",
 		"datetime_precision",
 		"CREATE_TABLE_tt_(pk_int_primary_key,_d_datetime(6)_default_current_timestamp(6))",
 		"Identifier_lengths",
 		"table_charset_options",
-		// "show_create_table_t3",
-		// "show_create_table_t4",
-		// "create_table_with_select_preserves_default",
-		// "create_table_t1_select_*_from_a;",
-		// "create_table_t2_select_j_from_a;",
-		// "create_table_t3_select_j_as_i_from_a;",
-		// "create_table_t4_select_j_+_1_from_a;",
-		// "create_table_t5_select_a.j_from_a;",
-		// "create_table_t6_select_sqa.j_from_(select_i,_j_from_a)_sqa;",
-		// "show_create_table_t7;",
-		// "create_table_t8_select_*_from_(select_*_from_a)_a_join_(select_*_from_b)_b;",
-		// "show_create_table_t9;",
-		// "create_table_t11_select_sum(j)_over()_as_jj_from_a;",
-		// "create_table_t12_select_j_from_a_group_by_j;",
-		// "create_table_t13_select_*_from_c;",
 		"event_contains_CREATE_TABLE_AS",
 		"CREATE_EVENT_foo_ON_SCHEDULE_EVERY_1_YEAR_DO_CREATE_TABLE_bar_AS_SELECT_1;",
 		"trigger_contains_CREATE_TABLE_AS",