Hibernate (or EntityManager?) adding "where 0=1" to query

Question

I'm using the JPA EntityManager + Hiberate, and a myserious piece of the where clause is appearing. The debug from Hibernate is basically showing:

select /* bunch of columns */
from some_table
where /* several filters */
  and 0=1

This is happening when running javax.persistence.Query.getResultList. The Query has an array of Predicates in its where clause, but rest assured that 0 = 1 is not one of them.

I can find no possible reason why the 0=1 part is included in the query. Any ideas? I'd search for an answer first, but search engines ignore =.

score 8 · Accepted Answer · answered Jun 06 '13 at 22:12

8

This is how a disjunction is translated to SQL. See the javadoc for disjunction()

Create a disjunction (with zero disjuncts). A disjunction with zero disjuncts is false.

So, when an empty disjunction is created, it only contains the clause 1 = 0 (false). When additional predicates are added to the disjunction, they're simply added to the initial (false) one, separated with an or:

where 1 = 0 or ...

If you use a conjunction, it will be translated to

where 1 = 1 and ...

answered Jun 06 '13 at 22:12

JB Nizet

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Bingo. I just debugged through my code that's creating the Predicates and found that it build a disjunction with nothing in it. Problem solved. Thanks! – Depressio Jun 06 '13 at 22:13

score 1 · Answer 2 · answered Apr 07 '22 at 09:41

Similar to @JB Nizet answer, but to make it more concrete. In my case, I am using a CriteriaBuilder and the issue is that I am creating a list of predicates programmatically. In some cases, it generates an empty list of predicates and when I apply:

criteriaQuery.where(criteriaBuilder.and(predicates.toArray(new Predicate[] {})));

Appears the 0=1 issue. Simply checking if the predicates list is empty or not, and avoiding to adding to the where clause in the case it is empty, solves the issue.

Hibernate (or EntityManager?) adding "where 0=1" to query

2 Answers2