added RowScanner.Columns and RowsScanner.Columns

Author: ungerik

Diff for: errors.go

@@ -226,6 +226,10 @@ func (e rowScannerWithError) ScanStrings() ([]string, error) {
 	return nil, e.err
 }
 
+func (e rowScannerWithError) Columns() ([]string, error) {
+	return nil, e.err
+}
+
 // RowsScannerWithError
 
 // RowsScannerWithError returns a dummy RowsScanner
@@ -246,6 +250,10 @@ func (e rowsScannerWithError) ScanStructSlice(dest any) error {
 	return e.err
 }
 
+func (e rowsScannerWithError) Columns() ([]string, error) {
+	return nil, e.err
+}
+
 func (e rowsScannerWithError) ScanAllRowsAsStrings(headerRow bool) ([][]string, error) {
 	return nil, e.err
 }

Diff for: impl/rowscanner.go

@@ -71,6 +71,10 @@ func (s *RowScanner) ScanStrings() ([]string, error) {
 	return ScanStrings(s.rows)
 }
 
+func (s *RowScanner) Columns() ([]string, error) {
+	return s.rows.Columns()
+}
+
 // CurrentRowScanner calls Rows.Scan without Rows.Next and Rows.Close
 type CurrentRowScanner struct {
 	Rows             Rows
@@ -93,6 +97,10 @@ func (s CurrentRowScanner) ScanStrings() ([]string, error) {
 	return ScanStrings(s.Rows)
 }
 
+func (s CurrentRowScanner) Columns() ([]string, error) {
+	return s.Rows.Columns()
+}
+
 // SingleRowScanner always uses the same Row
 type SingleRowScanner struct {
 	Row              Row
@@ -114,3 +122,7 @@ func (s SingleRowScanner) ScanValues() ([]any, error) {
 func (s SingleRowScanner) ScanStrings() ([]string, error) {
 	return ScanStrings(s.Row)
 }
+
+func (s SingleRowScanner) Columns() ([]string, error) {
+	return s.Row.Columns()
+}

Diff for: impl/rowsscanner.go

@@ -39,6 +39,10 @@ func (s *RowsScanner) ScanStructSlice(dest any) error {
 	return nil
 }
 
+func (s *RowsScanner) Columns() ([]string, error) {
+	return s.rows.Columns()
+}
+
 func (s *RowsScanner) ScanAllRowsAsStrings(headerRow bool) (rows [][]string, err error) {
 	cols, err := s.rows.Columns()
 	if err != nil {

Diff for: rowscanner.go

@@ -18,4 +18,7 @@ type RowScanner interface {
 	// nil (SQL NULL) will be converted to an empty string,
 	// all other types are converted with fmt.Sprint(src).
 	ScanStrings() ([]string, error)
+
+	// Columns returns the column names.
+	Columns() ([]string, error)
 }

Diff for: rowsscanner.go

@@ -24,6 +24,9 @@ type RowsScanner interface {
 	// with the column names will be prepended.
 	ScanAllRowsAsStrings(headerRow bool) (rows [][]string, err error)
 
+	// Columns returns the column names.
+	Columns() ([]string, error)
+
 	// ForEachRow will call the passed callback with a RowScanner for every row.
 	// In case of zero rows, no error will be returned.
 	ForEachRow(callback func(RowScanner) error) error