Question

我有一个像这样的mysql查询来获取行号。

set @rank = 0; 
select @rank := @rank + 1 as rank,id,name from test

在休眠3'：='是一个问题。

session.createSQLQuery("set @rank = 0; 
                        select @rank := @rank + 1 as rank,id,name from test");

我切换到休眠3到4并使用转义字符。

session.createSQLQuery("set @rank = 0; 
                        select @rank \\:= @rank + 1 as rank,id,name from test");

现在发生了另一个例外。它给出了例外：

"Parameter rank does not exist as a named parameter"

我试过了：

 session.createSQLQuery("select :rank \\:= :rank + 1 as rank,
                         ID,NAME,SURNAME from test").setInteger("rank", 0)

这次它给出了这个例外：

You have an error in your SQL syntax; check the manual that corresponds to 
your MySQL server version for the right syntax to use near ':= 0 + 1 as rank,id,
name from test' at line 1

我知道如何解决这个问题？

Answer 1

使用doReturningWork（）时，您可以访问普通的JDBC连接。然后你应该将SQL分成2个执行（设置和选择）：

final Object queryResultObject = session.doReturningWork(new ReturningWork<ReturnObjectType>() {

  @Override
  public ReturnObjectType execute(Connection connection) throws SQLException {

    final Statement statement = connection.createStatement();
    statement.execute("set @rank = 0");

    final ResultSet resultSet = statement.executeQuery(
                                      "select @rank := @rank + 1 as rank,id,name
                                       from test");

    ReturnObjectType result = /* transform ResultSet into return value */

    return result;
  }
});

Answer 2

Hibernate不支持特定于数据库的SQL语法或SQL局部变量。

从我看到你甚至不想选择某个实体，所以你只需要一个聚合查询：

select count(t), t.id, t.name 
from Test t
group by t.id, t.name

假设您有一个Test实体映射到测试表。

Hibernate createSqlQuery设置变量

2 个答案: