planner: fix wrong row compare logic in expression_rewriter (#8241)

pingcap · Nov 8, 2018 · 6c242ad · 6c242ad
1 parent d125958
commit 6c242ad
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Showing 2 changed files with 20 additions and 0 deletions.
diff --git a/planner/core/expression_rewriter.go b/planner/core/expression_rewriter.go
@@ -220,6 +220,18 @@ func (er *expressionRewriter) constructBinaryOpFunction(l expression.Expression,
 		if err != nil {
 			return nil, errors.Trace(err)
 		}
+		if evalexpr, ok := expr1.(*expression.Constant); ok {
+			_, isNull, err1 := evalexpr.EvalInt(er.ctx, chunk.Row{})
+			if err1 != nil || isNull {
+				return expr1, err1
+			}
+		}
+		if evalexpr, ok := expr2.(*expression.Constant); ok {
+			_, isNull, err1 := evalexpr.EvalInt(er.ctx, chunk.Row{})
+			if err1 != nil || isNull {
+				return expr2, err1
+			}
+		}
 		expr3, err = er.constructBinaryOpFunction(l, r, op)
 		if err != nil {
 			return nil, errors.Trace(err)

diff --git a/planner/core/expression_test.go b/planner/core/expression_test.go
@@ -241,6 +241,14 @@ func (s *testExpressionSuite) TestCompareRow(c *C) {
 			exprStr:   "row(1+3,2,3)<>row(1+3,2,3)",
 			resultStr: "0",
 		},
+		{
+			exprStr:   "row(1,2,3)<row(1,NULL,3)",
+			resultStr: "<nil>",
+		},
+		{
+			exprStr:   "row(1,2,3)<row(2,NULL,3)",
+			resultStr: "1",
+		},
 	}
 	s.runTests(c, tests)
 }