func getIdentValueFromOuterQuery(ctx context.Context, name string) (interface{}, error) {
s := getRowStack(ctx)
if s == nil {
return nil, errors.Errorf("unknown field %s", name)
}
// The top is current RowStack, use its last.
n := len(s.items) - 2
var (
v interface{}
err error
)
for ; n >= 0; n-- {
t := s.items[n]
// first try to get from outer table reference.
if t.FromData != nil {
v, err = GetIdentValue(name, t.FromDataFields, t.FromData)
if err == nil {
// tell current subquery using outer query
subquery.SetOuterQueryUsed(ctx)
return v, nil
}
}
// then try to get from outer select list.
if t.OutData != nil {
v, err = GetIdentValue(name, t.OutDataFields, t.OutData)
if err == nil {
// tell current subquery using outer query
subquery.SetOuterQueryUsed(ctx)
return v, nil
}
}
}
return nil, errors.Errorf("unknown field %s", name)
}
func (s *testSubQuerySuite) TestSubQuery(c *C) {
e := &subquery.SubQuery{
Val: 1,
}
ctx := mock.NewContext()
c.Assert(e.IsStatic(), IsFalse)
str := e.String()
c.Assert(str, Equals, "")
ec := e.Clone()
v, err := ec.Eval(ctx, nil)
c.Assert(err, IsNil)
c.Assert(v, Equals, 1)
e2, ok := ec.(*subquery.SubQuery)
c.Assert(ok, IsTrue)
e2 = newMockSubQuery([][]interface{}{{1}}, []string{"id"})
vv, err := e2.Eval(ctx, nil)
c.Assert(err, IsNil)
c.Assert(vv, Equals, 1)
e2.SetValue(nil)
vv, err = e2.Eval(ctx, nil)
c.Assert(err, IsNil)
c.Assert(vv, Equals, 1)
e2 = newMockSubQuery([][]interface{}{{1, 2}}, []string{"id", "name"})
vv, err = e2.Eval(ctx, nil)
c.Assert(err, IsNil)
c.Assert(vv, DeepEquals, []interface{}{1, 2})
e2 = newMockSubQuery([][]interface{}{{1}, {2}}, []string{"id"})
_, err = e2.Eval(ctx, nil)
c.Assert(err, NotNil)
str = e2.String()
c.Assert(len(str), Greater, 0)
e2 = newMockSubQuery([][]interface{}{{1, 2}}, []string{"id", "name"})
count, err := e2.ColumnCount(nil)
c.Assert(err, IsNil)
c.Assert(count, Equals, 2)
count, err = e2.ColumnCount(nil)
c.Assert(err, IsNil)
c.Assert(count, Equals, 2)
e3 := newMockSubQuery([][]interface{}{{1, 2}}, []string{"id", "name"})
e2.Push(ctx)
e3.Push(ctx)
c.Assert(e2.UseOuter, IsFalse)
c.Assert(e3.UseOuter, IsFalse)
subquery.SetOuterQueryUsed(ctx)
c.Assert(e2.UseOuterQuery, IsTrue)
c.Assert(e3.UseOuterQuery, IsTrue)
err = e2.Pop(ctx)
c.Assert(err, NotNil)
err = e3.Pop(ctx)
subquery.SetOuterQueryUsed(ctx)
err = e2.Pop(ctx)
c.Assert(err, IsNil)
err = e2.Pop(ctx)
c.Assert(err, NotNil)
subquery.SetOuterQueryUsed(ctx)
c.Assert(len(subquery.SubQueryStackKey.String()), Greater, 0)
}