From dbd7b61404b10bf9d701647c325f945e321e25f6 Mon Sep 17 00:00:00 2001
From: HuaiyuXu <391585975@qq.com>
Date: Sat, 21 Jul 2018 10:52:44 +0800
Subject: [PATCH] plan, executor: check b.err after buildSort and buildLimit in
 builUnion (#7114)

---
 executor/prepared_test.go    | 3 +++
 plan/logical_plan_builder.go | 8 ++++++++
 2 files changed, 11 insertions(+)

diff --git a/executor/prepared_test.go b/executor/prepared_test.go
index 0a919a904980e..64c74a90ad7e8 100644
--- a/executor/prepared_test.go
+++ b/executor/prepared_test.go
@@ -263,4 +263,7 @@ func (s *testSuite) TestPreparedNameResolver(c *C) {
 	tk.MustExec("prepare stmt from 'select * from t limit ? offset ?'")
 	_, err := tk.Exec("prepare stmt from 'select b from t'")
 	c.Assert(err.Error(), Equals, "[planner:1054]Unknown column 'b' in 'field list'")
+
+	_, err = tk.Exec("prepare stmt from '(select * FROM t) union all (select * FROM t) order by a limit ?'")
+	c.Assert(err.Error(), Equals, "[planner:1054]Unknown column 'a' in 'order clause'")
 }
diff --git a/plan/logical_plan_builder.go b/plan/logical_plan_builder.go
index dc10ceb4f278e..36723e7d7dfb7 100644
--- a/plan/logical_plan_builder.go
+++ b/plan/logical_plan_builder.go
@@ -701,9 +701,17 @@ func (b *planBuilder) buildUnion(union *ast.UnionStmt) LogicalPlan {
 
 	if union.OrderBy != nil {
 		unionPlan = b.buildSort(unionPlan, union.OrderBy.Items, nil)
+		if b.err != nil {
+			b.err = errors.Trace(b.err)
+			return nil
+		}
 	}
 	if union.Limit != nil {
 		unionPlan = b.buildLimit(unionPlan, union.Limit)
+		if b.err != nil {
+			b.err = errors.Trace(b.err)
+			return nil
+		}
 	}
 	return unionPlan
 }