func (s *SelectStmt) checkOneColumn(ctx context.Context) error {
// check select fields
for _, f := range s.Fields {
if err := expressions.CheckOneColumn(ctx, f.Expr); err != nil {
return errors.Trace(err)
}
}
// check group by
if s.GroupBy != nil {
for _, f := range s.GroupBy.By {
if err := expressions.CheckOneColumn(ctx, f); err != nil {
return errors.Trace(err)
}
}
}
// check order by
if s.OrderBy != nil {
for _, f := range s.OrderBy.By {
if err := expressions.CheckOneColumn(ctx, f.Expr); err != nil {
return errors.Trace(err)
}
}
}
// check having
if s.Having != nil {
if err := expressions.CheckOneColumn(ctx, s.Having.Expr); err != nil {
return errors.Trace(err)
}
}
return nil
}
// CheckAndUpdateSelectList checks having fields validity and set hidden fields to selectList.
func (r *HavingRset) CheckAndUpdateSelectList(selectList *plans.SelectList, groupBy []expression.Expression, tableFields []*field.ResultField) error {
if err := expressions.CheckOneColumn(r.Expr); err != nil {
return errors.Trace(err)
}
if expressions.ContainAggregateFunc(r.Expr) {
expr, err := selectList.UpdateAggFields(r.Expr, tableFields)
if err != nil {
return errors.Errorf("%s in 'having clause'", err.Error())
}
r.Expr = expr
} else {
// having can only contain group by column and select list, e.g,
// `select c1 from t group by c2 having c3 > 0` is invalid,
// because c3 is not in group by and select list.
names := expressions.MentionedColumns(r.Expr)
for _, name := range names {
found := false
// check name whether in select list.
// notice that `select c1 as c2 from t group by c1, c2, c3 having c2 > c3`,
// will use t.c2 not t.c1 here.
if field.ContainFieldName(name, selectList.ResultFields, field.OrgFieldNameFlag) {
continue
}
if field.ContainFieldName(name, selectList.ResultFields, field.FieldNameFlag) {
if field.ContainFieldName(name, tableFields, field.OrgFieldNameFlag) {
selectList.CloneHiddenField(name, tableFields)
}
continue
}
// check name whether in group by.
// group by must only have column name, e.g,
// `select c1 from t group by c2 having c2 > 0` is valid,
// but `select c1 from t group by c2 + 1 having c2 > 0` is invalid.
for _, by := range groupBy {
if !field.CheckFieldsEqual(name, by.String()) {
continue
}
// if name is not in table fields, it will get an unknown field error in GroupByRset,
// so no need to check return value.
selectList.CloneHiddenField(name, tableFields)
found = true
break
}
if !found {
return errors.Errorf("Unknown column '%s' in 'having clause'", name)
}
}
}
return nil
}
// CheckAndUpdateSelectList checks order by fields validity and set hidden fields to selectList.
func (r *OrderByRset) CheckAndUpdateSelectList(selectList *plans.SelectList, tableFields []*field.ResultField) error {
for i, v := range r.By {
if err := expressions.CheckOneColumn(v.Expr); err != nil {
return errors.Trace(err)
}
if expressions.ContainAggregateFunc(v.Expr) {
expr, err := selectList.UpdateAggFields(v.Expr, tableFields)
if err != nil {
return errors.Errorf("%s in 'order clause'", err.Error())
}
r.By[i].Expr = expr
} else {
names := expressions.MentionedColumns(v.Expr)
for _, name := range names {
// try to find in select list
// TODO: mysql has confused result for this, see #555.
// now we use select list then order by, later we should make it easier.
if field.ContainFieldName(name, selectList.ResultFields, field.CheckFieldFlag) {
// check ambiguous fields, like `select c1 as c2, c2 from t order by c2`.
if err := field.CheckAmbiguousField(name, selectList.ResultFields, field.DefaultFieldFlag); err != nil {
return errors.Errorf("Column '%s' in order statement is ambiguous", name)
}
continue
}
if !selectList.CloneHiddenField(name, tableFields) {
return errors.Errorf("Unknown column '%s' in 'order clause'", name)
}
}
}
}
return nil
}
// ResolveSelectList gets fields and result fields from selectFields and srcFields,
// including field validity check and wildcard field processing.
func ResolveSelectList(selectFields []*field.Field, srcFields []*field.ResultField) (*SelectList, error) {
selectList := &SelectList{
Fields: make([]*field.Field, 0, len(selectFields)),
ResultFields: make([]*field.ResultField, 0, len(selectFields)),
AggFields: make(map[int]struct{}),
}
wildcardNum := 0
for _, v := range selectFields {
if err := expressions.CheckOneColumn(v.Expr); err != nil {
return nil, errors.Trace(err)
}
// Check metioned field.
names := expressions.MentionedColumns(v.Expr)
if len(names) == 0 {
selectList.AddField(v, nil)
continue
}
// Check wildcard field.
name := names[0]
table, ok, err := field.CheckWildcardField(name)
if err != nil {
return nil, err
}
if ok {
// Check unqualified wildcard field number,
// like `select *, * from t`.
if table == "" {
wildcardNum++
if wildcardNum > 1 {
return nil, errors.Errorf("wildcard field exist more than once")
}
}
selectList.updateFields(table, srcFields)
continue
}
var result *field.ResultField
if err = field.CheckAllFieldNames(names, srcFields, field.DefaultFieldFlag); err != nil {
return nil, errors.Trace(err)
}
if _, ok := v.Expr.(*expressions.Ident); ok {
// Field is ident.
if result, err = field.CloneFieldByName(name, srcFields, field.DefaultFieldFlag); err != nil {
return nil, errors.Trace(err)
}
// Maybe alias name or only column name.
if !expressions.IsQualified(v.Name) {
result.Name = v.Name
}
} else {
// The field is not an ident, maybe binary expression,
// like `select c1 + c2`, or `select c1 + 10`, etc.
result = &field.ResultField{Name: v.Name}
}
selectList.AddField(v, result)
}
selectList.HiddenFieldOffset = len(selectList.Fields)
selectList.resolveAggFields()
if selectList.HiddenFieldOffset == 0 {
return nil, errors.Errorf("invalid empty select fields")
}
return selectList, nil
}
