plan: fix a panic bug. (pingcap#1914)

executor/aggregate_test.go

@@ -136,6 +136,8 @@ func (s *testSuite) TestAggregation(c *C) {
 	result.Check(testkit.Rows())
 	result = tk.MustQuery("select count(*) from t a join t b where a.c < 0")
 	result.Check(testkit.Rows("0"))
+	result = tk.MustQuery("select sum(b.c), count(b.d), a.c from t a left join t b on a.c = b.d group by b.d order by b.d")
+	result.Check(testkit.Rows("<nil> 0 4", "8 12 1", "5 2 3"))
 	// This two cases prove that having always resolve name from field list firstly.
 	result = tk.MustQuery("select 1-d as d from t having d < 0 order by d desc")
 	result.Check(testkit.Rows("-1", "-1", "-2", "-2"))

plan/physical_plan_builder.go

@@ -630,17 +630,18 @@ func (p *Aggregation) convert2PhysicalPlanStream(prop *requiredProperty) (*physi
 		props: make([]*columnProp, 0, len(gbyCols)),
 	}
 	for _, pro := range prop.props {
-		isMatch := false
+		var matchedCol *expression.Column
 		for i, col := range gbyCols {
-			if col.ColName.L == pro.col.ColName.L {
+			if !col.Correlated && col.ColName.L == pro.col.ColName.L {
 				isSortKey[i] = true
-				isMatch = true
+				matchedCol = col
 			}
 		}
-		if !isMatch {
+		if matchedCol == nil {
 			return info, nil
 		}
-		newProp.props = append(newProp.props, pro)
+		// We should add columns in aggregation in order to keep index right.
+		newProp.props = append(newProp.props, &columnProp{col: matchedCol, desc: pro.desc})
 	}
 	newProp.sortKeyLen = len(newProp.props)
 	for i, col := range gbyCols {