ast, plan: return error when the arg of VALUES() function is not a co…

…lumn (#7817)

ast/expressions.go

@@ -927,7 +927,9 @@ func (n *ValuesExpr) Accept(v Visitor) (Node, bool) {
 	if !ok {
 		return n, false
 	}
-	n.Column = node.(*ColumnNameExpr)
+	// `node` may be *ast.ValueExpr, to avoid panic, we write `ok` but do not use
+	// it.
+	n.Column, ok = node.(*ColumnNameExpr)
 	return v.Leave(n)
 }
 

planner/core/logical_plan_builder.go

@@ -1164,6 +1164,10 @@ func (g *gbyResolver) Leave(inNode ast.Node) (ast.Node, bool) {
 			return inNode, false
 		}
 		return ret, true
+	case *ast.ValuesExpr:
+		if v.Column == nil {
+			g.err = ErrUnknownColumn.GenWithStackByArgs("", "VALUES() function")
+		}
 	}
 	return inNode, true
 }

planner/core/logical_plan_test.go

@@ -1985,6 +1985,7 @@ func (s *testPlanSuite) TestNameResolver(c *C) {
 		{"select a from t group by t11.c1", "[planner:1054]Unknown column 't11.c1' in 'group statement'"},
 		{"delete a from (select * from t ) as a, t", "[planner:1288]The target table a of the DELETE is not updatable"},
 		{"delete b from (select * from t ) as a, t", "[planner:1109]Unknown table 'b' in MULTI DELETE"},
+		{"select '' as fakeCol from t group by values(fakeCol)", "[planner:1054]Unknown column '' in 'VALUES() function'"},
 		{"update t, (select * from t) as b set b.a = t.a", "[planner:1288]The target table b of the UPDATE is not updatable"},
 	}