diff --git a/tools/search/query.go b/tools/search/query.go
index ff56f1ac..5646b912 100644
--- a/tools/search/query.go
+++ b/tools/search/query.go
@@ -98,7 +98,7 @@ func pgSql(driver string, t *resolveSearchTag, condition Condition, qValue refle
 		condition.SetWhere(fmt.Sprintf("%s.%s in (?)", t.Table, t.Column), []interface{}{qValue.Field(i).Interface()})
 	case "isnull":
 		if !(qValue.Field(i).IsZero() && qValue.Field(i).IsNil()) {
-			condition.SetWhere(fmt.Sprintf("%s.%s isnull", t.Table, t.Column), make([]interface{}, 0))
+			condition.SetWhere(fmt.Sprintf("%s.%s is null", t.Table, t.Column), make([]interface{}, 0))
 		}
 	case "order":
 		switch strings.ToLower(qValue.Field(i).String()) {