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

Escaping the MySQL Assign (=) Operator in Hibernate Native Queries

When working with Hibernate native queries, it's possible to encounter errors while using the MySQL assign operator (:=) due to the space following the colon (:). This issue is particularly evident in cases where subselect statements are necessary.

The provided code illustrates this:

SELECT sub.rownum FROM (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) AS sub WHERE sub.id = :nid

Executing this query using setParameter results in an exception highlighting the erroneous space after the colon.

Fortunately, Hibernate now provides a solution to this issue. In Hibernate 4.1.3 and later, you can escape the assign operator using a backslash (), as shown below:

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

By escaping the colon, Hibernate successfully interprets the syntax, allowing you to execute subselect queries effectively.

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