java - hibernate : convert mysql Query Datedif to HQL Query

Question

这是我在 mysql 中的查询

SELECT DATEDIFF('2008-11-30','2008-11-29') AS DiffDate

如何转换为 Hibernate 查询语言

Answer 1

实现此目的的方法之一是扩展 mysql 方言并使用 registerFunction(String, SQLFunction) 注册它。

public class CustomMySQL5InnoDBDialect extends MySQL5InnoDBDialect {

  public CustomMySQL5InnoDBDialect () {
    super();
    registerFunction( "datediff", new SQLFunctionTemplate( StandardBasicTypes.INTEGER, "datediff(?1, ?2)" ) );
 }

}