如何在休眠本机查询中使用 MySQL 分配运算符 (:=)？

Question

I'm using Hibernate. I wrote some native query because I need to use sub select statement.

Query looks like 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

When I run this query like this:

sessionFactory.getCurrentSession()
    .createSQLQuery(query)
    .setParameter("kid", kid)
    .setParameter("nid", nid)
    .uniqueResult();

This exception comes out:

org.hibernate.QueryException: Space is not allowed after parameter prefix ':' ....

This might because of := operator. I found some Hibernate issue about this. This issue is still open. Isn't there any solution for this problem?

Answer 1

Note that HHH-2697 is now fixed for Hibernate 4.1.3 You can now escape with backslash:

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

Answer 2

Another solution for those of us who can't make the jump to Hibernate 4.1.3.
Simply use /*'*/:=/*'*/ inside the query. Hibernate code treats everything between ' as a string (ignores it). MySQL on the other hand will ignore everything inside a blockquote and will evaluate the whole expression to an assignement operator.
I know it's quick and dirty, but it get's the job done without stored procedures, interceptors etc.

Answer 3

you can implement this is a slightly different way.. you need to replace the : operator with something else (say '|' char ) and in your interceptor replace the '|' with the : .

this way hibernate will not try to think the : is a param but will ignore it

For the interceptor logic you can refer to the hibernate manual

This has worked for me using MySQL 5.

remember, this replacing of : must be only done to ':=' and other MySQL specific requirments.. don't try to replace the : for the param-placeholders. (hibernate will not be able to identify the params then)

Answer 4

我更喜欢包含 Spring JDBC 并执行查询，而不是与 Hibernate 拦截器作斗争。

Answer 5

在遇到 mysql时的Hibernate 异常中：= operator 提供了除拦截器之外的另一个选项来解决此问题

Answer 6

If you keep your SQL-files away from Java code - try this piece of code. Played a lot to get the right number of escaping slashes:

String sqlPattern = FileUtils.readFile(this.getClass(), /sql/my_query.sql");
sqlPattern = sqlPattern.replaceAll(":=", "\\\\:=");
Query query = entityManager.createNativeQuery(sqlPattern);

Answer 7

我想在 = 之后不应该有空格，运算符应该写为 =:（没有任何空格）