Add support for scanning columns (#5)

Reviewed-on: #5

query.go

@@ -119,6 +119,23 @@ func (q *Query) MustExec() {
 	}
 }
 
+func (q *Query) ScanColumns(results *[]string) *Query {
+	if q.err != nil {
+		return q
+	}
+
+	// Ensure the number of results matches the number of columns
+	if q.stmt.ColumnCount() != len(*results) {
+		*results = make([]string, q.stmt.ColumnCount())
+	}
+
+	// Fetch the column names
+	for i := 0; i < q.stmt.ColumnCount(); i++ {
+		(*results)[i] = q.stmt.ColumnName(i)
+	}
+	return q
+}
+
 func (q *Query) ScanSingle(results ...any) (rerr error) {
 	defer q.unlock()
 	// Scan rows

query_test.go

@@ -35,6 +35,19 @@ func TestScanWithMissingValues(t *testing.T) {
 	require.Equal(t, ErrMissingScan, err)
 }
 
+func TestScanColumns(t *testing.T) {
+	db := openTestDb(t)
+	var columns []string
+	var key string
+	err := db.Query("select `key` from mytable").
+		ScanColumns(&columns).
+		ScanSingle(&key)
+	require.NoError(t, err, "expected no error scanning columns")
+	require.Equal(t, 1, len(columns), "expected one column")
+	require.Equal(t, "key", columns[0], "expected column name 'key'")
+	require.Equal(t, "foo", key, "expected key to be 'foo'")
+}
+
 func TestBindInt64(t *testing.T) {
 	db := openTestDb(t)
 	var value int64