ERROR: syntax error at or near "$1" postgresql query with params

Question

I have a postgres query with params, in my Java code, am using stringBuilder to build the query and then createNativeQuery to create query and populating the params. However if I run the query in my gui, it gives me the result which is expected, but gives error when executing via code. I'm a newbie on postgres and have seen some questions with the nearly same problems that I need to cast the params in the query, but I do have IN param inside my query which is list, I've tried some solutions but didn't worked.

I' am getting error as :-> "error": "Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.5.1.v20130918-f2b9fc5): org.eclipse.persistence.exceptions.DatabaseException Internal Exception: org.postgresql.util.PSQLException: ERROR: syntax error at or near "$1" Position: 249

        StringBuilder sb = new StringBuilder();
        sb.append(" SELECT comments.comment, mapping.user_id, 
        mapping.comment_id, mapping.comment_state, 
        mapping.created_at  FROM comments ").append(" comment 
        JOIN ").
        append(" user_comment_mapping  mapping ON 
        mapping.comment_id = comment.id WHERE 
        mapping.user_id IN ? AND mapping.comment_state = ? 
        ");

        final Query query = em.createNativeQuery(sb.toString());
        query.setParameter("1", userIds);
        query.setParameter("2", 
        2);

        List<Object[]> list = query.getResultList();

Thanks!

Answer 1

It seems you are mixing between parameter holder and name so.

If you want to use holder :

mapping.user_id IN ? AND mapping.comment_state = ? 

then

query.setParameter(1, userIds);
query.setParameter(2, 2);

If you want to use names :

mapping.user_id IN :ids AND mapping.comment_state = :stat


query.setParameter("ids", userIds);
query.setParameter("stat", 2);