Merge pull request #113 from pingcap/siddontang/in-with-subquery

expressions,parser: IN expression uses subquery

expression/expressions/in.go

@@ -24,7 +24,6 @@ import (
 	"github.com/juju/errors"
 	"github.com/pingcap/tidb/context"
 	"github.com/pingcap/tidb/expression"
-	"github.com/pingcap/tidb/plan"
 	"github.com/pingcap/tidb/util/types"
 )
 
@@ -40,8 +39,8 @@ type PatternIn struct {
 	List []expression.Expression
 	// Not is true, the expression is "not in".
 	Not bool
-	// Sel is the select statement.
-	Sel plan.Planner
+	// Sel is the sub query.
+	Sel *SubQuery
 }
 
 // Clone implements the Expression Clone interface.
@@ -93,10 +92,10 @@ func (n *PatternIn) String() string {
 	}
 
 	if n.Not {
-		return fmt.Sprintf("%s NOT IN (%s)", n.Expr, n.Sel)
+		return fmt.Sprintf("%s NOT IN %s", n.Expr, n.Sel)
 	}
 
-	return fmt.Sprintf("%s IN (%s)", n.Expr, n.Sel)
+	return fmt.Sprintf("%s IN %s", n.Expr, n.Sel)
 }
 
 func (n *PatternIn) checkInList(in interface{}, list []interface{}) (interface{}, error) {
@@ -166,21 +165,16 @@ func (n *PatternIn) Eval(ctx context.Context, args map[interface{}]interface{})
 
 	var res []interface{}
 	if ev, ok := args[n]; !ok {
+		if err := hasSameColumnCount(ctx, n.Expr, n.Sel); err != nil {
+			return nil, errors.Trace(err)
+		}
+
 		// select not yet evaluated
 		r, err := n.Sel.Plan(ctx)
 		if err != nil {
 			return nil, err
 		}
 
-		count, countErr := columnCount(ctx, n.Expr)
-		if countErr != nil {
-			return nil, errors.Trace(countErr)
-		}
-
-		if g, e := len(r.GetFields()), count; g != e {
-			return false, errors.Errorf("IN (%s): mismatched field count, have %d, need %d", n.Sel, g, e)
-		}
-
 		res = []interface{}{}
 		// evaluate select and save its result for later in expression check
 		err = r.Do(ctx, func(id interface{}, data []interface{}) (more bool, err error) {

expression/expressions/in_test.go

@@ -84,7 +84,7 @@ func (t *testPatternInSuite) TestPatternIn(c *C) {
 	c.Assert(err, IsNil)
 	c.Assert(vvv, IsNil)
 
-	sel := newMockStatement()
+	sel := newMockSubQuery([][]interface{}{{1, 2}}, []string{"id", "name"})
 	e2.Sel = sel
 
 	str = e2.String()
@@ -101,8 +101,7 @@ func (t *testPatternInSuite) TestPatternIn(c *C) {
 	_, err = e2.Eval(nil, args)
 	c.Assert(err, NotNil)
 
-	sel.SetFieldOffset(1)
-	e2.Sel = sel
+	e2.Sel = newMockSubQuery([][]interface{}{{1}, {2}}, []string{"id"})
 
 	vv, err = e2.Eval(nil, args)
 	c.Assert(err, IsNil)
@@ -116,12 +115,12 @@ func (t *testPatternInSuite) TestPatternIn(c *C) {
 
 	delete(args, e2)
 	e2.Expr = newTestRow(1, 2)
-	sel.SetFieldOffset(2)
+	e2.Sel = newMockSubQuery([][]interface{}{{1, 2}}, []string{"id", "name"})
 	_, err = e2.Eval(nil, args)
 	c.Assert(err, IsNil)
 
 	e2.Expr = newTestRow(1, 2, 3)
-	sel.SetFieldOffset(2)
+
 	_, err = e2.Eval(nil, args)
 	c.Assert(err, NotNil)
 

parser/parser.y

@@ -1375,9 +1375,9 @@ Factor1:
 	{
 		$$ = &expressions.PatternIn{Expr: $1.(expression.Expression), Not: $2.(bool), List: $5.([]expression.Expression)}
 	}
-|	PrimaryFactor NotOpt "IN" '(' SelectStmt semiOpt ')'
+|	PrimaryFactor NotOpt "IN" SubSelect
 	{
-		$$ = &expressions.PatternIn{Expr: $1.(expression.Expression), Not: $2.(bool), Sel: $5.(*stmts.SelectStmt)}
+		$$ = &expressions.PatternIn{Expr: $1.(expression.Expression), Not: $2.(bool), Sel: $4.(*expressions.SubQuery)}
 	}
 |	PrimaryFactor NotOpt "BETWEEN" PrimaryFactor "AND" Factor1
 	{