RowTo(AddrOf)StructByPos ignores fields with "-" db tag

https://github.com/jackc/pgx/discussions/1682

rows.go

@@ -496,7 +496,8 @@ func (rs *mapRowScanner) ScanRow(rows Rows) error {
 }
 
 // RowToStructByPos returns a T scanned from row. T must be a struct. T must have the same number a public fields as row
-// has fields. The row and T fields will by matched by position.
+// has fields. The row and T fields will by matched by position. If the "db" struct tag is "-" then the field will be
+// ignored.
 func RowToStructByPos[T any](row CollectableRow) (T, error) {
 	var value T
 	err := row.Scan(&positionalStructRowScanner{ptrToStruct: &value})
@@ -504,7 +505,8 @@ func RowToStructByPos[T any](row CollectableRow) (T, error) {
 }
 
 // RowToAddrOfStructByPos returns the address of a T scanned from row. T must be a struct. T must have the same number a
-// public fields as row has fields. The row and T fields will by matched by position.
+// public fields as row has fields. The row and T fields will by matched by position. If the "db" struct tag is "-" then
+// the field will be ignored.
 func RowToAddrOfStructByPos[T any](row CollectableRow) (*T, error) {
 	var value T
 	err := row.Scan(&positionalStructRowScanner{ptrToStruct: &value})
@@ -545,6 +547,11 @@ func (rs *positionalStructRowScanner) appendScanTargets(dstElemValue reflect.Val
 		if sf.Anonymous && sf.Type.Kind() == reflect.Struct {
 			scanTargets = rs.appendScanTargets(dstElemValue.Field(i), scanTargets)
 		} else if sf.PkgPath == "" {
+			dbTag, _ := sf.Tag.Lookup(structTagKey)
+			if dbTag == "-" {
+				// Field is ignored, skip it.
+				continue
+			}
 			scanTargets = append(scanTargets, dstElemValue.Field(i).Addr().Interface())
 		}
 	}

rows_test.go

@@ -384,6 +384,24 @@ func TestRowToStructByPos(t *testing.T) {
 	})
 }
 
+func TestRowToStructByPosIgnoredField(t *testing.T) {
+	type person struct {
+		Name string
+		Age  int32 `db:"-"`
+	}
+
+	defaultConnTestRunner.RunTest(context.Background(), t, func(ctx context.Context, t testing.TB, conn *pgx.Conn) {
+		rows, _ := conn.Query(ctx, `select 'Joe' as name from generate_series(0, 9) n`)
+		slice, err := pgx.CollectRows(rows, pgx.RowToStructByPos[person])
+		require.NoError(t, err)
+
+		assert.Len(t, slice, 10)
+		for i := range slice {
+			assert.Equal(t, "Joe", slice[i].Name)
+		}
+	})
+}
+
 func TestRowToStructByPosEmbeddedStruct(t *testing.T) {
 	type Name struct {
 		First string