diff --git a/engine_test.go b/engine_test.go
index 0299ad20e..7864ed426 100644
--- a/engine_test.go
+++ b/engine_test.go
@@ -1226,6 +1226,10 @@ var queries = []struct {
 		`SELECT CASE i WHEN 1 THEN i ELSE NULL END FROM mytable`,
 		[]sql.Row{{int64(1)}, {nil}, {nil}},
 	},
+	{
+		`SELECT (NULL+1)`,
+		[]sql.Row{{nil}},
+	},
 }
 
 func TestQueries(t *testing.T) {
diff --git a/sql/expression/arithmetic.go b/sql/expression/arithmetic.go
index a1b69b5cd..ecdf26961 100644
--- a/sql/expression/arithmetic.go
+++ b/sql/expression/arithmetic.go
@@ -159,6 +159,10 @@ func (a *Arithmetic) Eval(ctx *sql.Context, row sql.Row) (interface{}, error) {
 		return nil, err
 	}
 
+	if lval == nil || rval == nil {
+		return nil, nil
+	}
+
 	lval, rval, err = a.convertLeftRight(lval, rval)
 	if err != nil {
 		return nil, err