// Do the real work to evaluate subquery.
func (e *Evaluator) subqueryExec(v ast.SubqueryExec) bool {
rowCount := 2
if e.multipleRows {
rowCount = -1
} else if e.existRow {
rowCount = 1
}
rows, err := v.EvalRows(e.ctx, rowCount)
if err != nil {
e.err = errors.Trace(err)
return false
}
if e.multipleRows || e.existRow {
v.SetValue(rows)
return true
}
switch len(rows) {
case 0:
v.SetValue(nil)
case 1:
v.SetValue(rows[0])
default:
e.err = errors.New("Subquery returns more than 1 row")
return false
}
return true
}
// Do the real work to evaluate subquery.
func (e *Evaluator) subqueryExec(v ast.SubqueryExec) bool {
rowCount := 2
if e.multipleRows {
rowCount = -1
} else if e.existRow {
rowCount = 1
}
rows, err := v.EvalRows(e.ctx, rowCount)
if err != nil {
e.err = errors.Trace(err)
return false
}
if e.multipleRows || e.existRow {
v.GetDatum().SetInterface(types.MakeDatums(rows...))
return true
}
switch len(rows) {
case 0:
v.GetDatum().SetNull()
case 1:
v.SetDatum(types.NewDatum(rows[0]))
default:
e.err = errors.New("Subquery returns more than 1 row")
return false
}
return true
}