[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-2776) Restrictons.in(..) generates invalid SQL if list of values is empty

Restrictons.in(..) generates invalid SQL if list of values is empty ------------------------------------------------------------------- Key: HHH-2776 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2776 Project: Hibernate Core Issue Type: Bug Components: query-criteria Affects Versions: 3.2.2 Environment: Hibernate 3.2.2.ga, MySQL 4.1.18, Windows XP Reporter: Adrian Smith I have classes called A and B. There is a 1:n relationship from A to B. Class B has the following in its mapping file: <many-to-one name="a" class="A" column="fk_a_id" not-null="true" /> If I write the following code: List<B> foo() { List<A> aList = .... Session session = .... Criteria query = session.createCriteria(B.class); query.add(Restrictions.in("a", aList)); return query.list(); } Then all works fine and the results I want are returned. However, if aList is empty (i.e. aList.size()==0) then the query.list function generates and executes invalid SQL for MySQL. java.sql.SQLException: Syntax error or access violation message from server: "You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ')' at line 1" I imagine that it is generating SQL like IN () which isn't valid. I realize it's a bit ridiculous to want to find the rows where a field is IN the empty list. Nothing will ever be returned. However, in my opinion it should still be allowed, and return no rows, just as saying "WHERE 1=2" is allowed, just doesn't return any rows.