How to Use MySQL Assign Operator (:=) in Hibernate Native Queries?

MySQL Assign Operator in Hibernate Native Query

When working with Hibernate, you may encounter the need to use subselect statements in native queries. Native queries allow you to directly interact with the underlying database using its own syntax.

However, attempting to use the MySQL assign operator (:=) in a native query within Hibernate may result in an exception: "Space is not allowed after parameter prefix ':' ....". This is due to a known issue (HHH-2697) with Hibernate.

Solution

Fortunately, Hibernate 4.1.3 and later versions have addressed this issue. To use the MySQL assign operator in a native query, you can now escape it with a backslash ().

For example, consider the following native query:

<code class="sql">SELECT k.`news_master_id` AS id, @row := @row + 1 AS rownum 
FROM keyword_news_list k 
JOIN (SELECT @row := 0) r 
WHERE k.`keyword_news_id` = :kid
ORDER BY k.`news_master_id` ASC</code>

To execute this query in Hibernate, use the following code:

<code class="java">sessionFactory.getCurrentSession()
    .createSQLQuery(query)
    .setParameter("kid", kid)
    .uniqueResult();</code>

By escaping the assign operator with a backslash, the query will execute successfully.

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