server: Correct the check for Resultset

mysql/result.go

@@ -34,3 +34,10 @@ func (r *Result) Close() {
 		r.Resultset = nil
 	}
 }
+
+func (r *Result) HasResultset() bool {
+	if r.Resultset != nil && len(r.Resultset.Fields) > 0 {
+		return true
+	}
+	return false
+}

mysql/result_test.go

@@ -0,0 +1,19 @@
+package mysql
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestHasResultset_false(t *testing.T) {
+	r := NewResultReserveResultset(0)
+	b := r.HasResultset()
+	require.Equal(t, false, b)
+}
+
+func TestHasResultset_true(t *testing.T) {
+	r := NewResultReserveResultset(1)
+	b := r.HasResultset()
+	require.Equal(t, true, b)
+}

server/resp.go

@@ -230,7 +230,7 @@ func (c *Conn) WriteValue(value interface{}) error {
 	case nil:
 		return c.writeOK(nil)
 	case *Result:
-		if v != nil && v.Resultset != nil {
+		if v != nil && v.HasResultset() {
 			return c.writeResultset(v.Resultset)
 		} else {
 			return c.writeOK(v)