TestEmptyTableOperations tests operations on tables with no rows. Note: basic empty SELECT is covered by TestProtocolSimpleQuery/empty_result. These tests cover UPDATE/DELETE returning 0 rows affected, aggregate NULL behavior, and JOINs where one side is empty.
(t *testing.T)
| 843 | // These tests cover UPDATE/DELETE returning 0 rows affected, aggregate NULL |
| 844 | // behavior, and JOINs where one side is empty. |
| 845 | func TestEmptyTableOperations(t *testing.T) { |
| 846 | t.Run("update_empty", func(t *testing.T) { |
| 847 | conn := openDuckgresConn(t) |
| 848 | defer func() { _ = conn.Close() }() |
| 849 | |
| 850 | mustExec(t, conn, "CREATE TABLE empty_update (id INTEGER, val TEXT)") |
| 851 | |
| 852 | result, err := conn.Exec("UPDATE empty_update SET val = 'changed' WHERE id = 1") |
| 853 | if err != nil { |
| 854 | t.Fatalf("UPDATE on empty table failed: %v", err) |
| 855 | } |
| 856 | affected, _ := result.RowsAffected() |
| 857 | if affected != 0 { |
| 858 | t.Errorf("Expected 0 rows affected, got %d", affected) |
| 859 | } |
| 860 | |
| 861 | mustExec(t, conn, "DROP TABLE empty_update") |
| 862 | }) |
| 863 | |
| 864 | t.Run("delete_empty", func(t *testing.T) { |
| 865 | conn := openDuckgresConn(t) |
| 866 | defer func() { _ = conn.Close() }() |
| 867 | |
| 868 | mustExec(t, conn, "CREATE TABLE empty_delete (id INTEGER)") |
| 869 | |
| 870 | result, err := conn.Exec("DELETE FROM empty_delete WHERE id = 1") |
| 871 | if err != nil { |
| 872 | t.Fatalf("DELETE on empty table failed: %v", err) |
| 873 | } |
| 874 | affected, _ := result.RowsAffected() |
| 875 | if affected != 0 { |
| 876 | t.Errorf("Expected 0 rows affected, got %d", affected) |
| 877 | } |
| 878 | |
| 879 | mustExec(t, conn, "DROP TABLE empty_delete") |
| 880 | }) |
| 881 | |
| 882 | t.Run("aggregate_empty", func(t *testing.T) { |
| 883 | conn := openDuckgresConn(t) |
| 884 | defer func() { _ = conn.Close() }() |
| 885 | |
| 886 | mustExec(t, conn, "CREATE TABLE empty_agg (id INTEGER, val DOUBLE)") |
| 887 | |
| 888 | var count int |
| 889 | if err := conn.QueryRow("SELECT COUNT(*) FROM empty_agg").Scan(&count); err != nil { |
| 890 | t.Fatalf("COUNT on empty failed: %v", err) |
| 891 | } |
| 892 | if count != 0 { |
| 893 | t.Errorf("COUNT: expected 0, got %d", count) |
| 894 | } |
| 895 | |
| 896 | var sum sql.NullFloat64 |
| 897 | if err := conn.QueryRow("SELECT SUM(val) FROM empty_agg").Scan(&sum); err != nil { |
| 898 | t.Fatalf("SUM on empty failed: %v", err) |
| 899 | } |
| 900 | if sum.Valid { |
| 901 | t.Errorf("SUM: expected NULL, got %f", sum.Float64) |
| 902 | } |
nothing calls this directly
no test coverage detected