Hibernate 如何在Grails HQL语句中按顺序排序
我有这样的关系:Hibernate 如何在Grails HQL语句中按顺序排序,hibernate,grails,sql-order-by,hql,Hibernate,Grails,Sql Order By,Hql,我有这样的关系: class Foo { static hasMany = [bars: Bar, things: Thing] } class Bar { // Has nothing to tie it back to Foo or Thing } class Thing { // Has nothing to tie it back to Foo or Bar } 我有以下带有以下参数的查询,其中大部分用于FlexGrid的分页。此查询通过Foo获取与Bar
class Foo {
static hasMany = [bars: Bar, things: Thing]
}
class Bar {
// Has nothing to tie it back to Foo or Thing
}
class Thing {
// Has nothing to tie it back to Foo or Bar
}
我有以下带有以下参数的查询,其中大部分用于FlexGrid的分页。此查询通过Foo
获取与Bar
的特定实例关联的Thing
的所有实例。因此,如果我的Bar
实例是Bar1
,那么我的查询将返回Thing1
和Thing2
:
def obj = Bar.get( 1 ) // Get Bar1
def max = params.int( "max" ) ?: 100 // Default max returned results is 100 unless otherwise specified
def offset = params.int( "offset" ) ?: 0 // Default offset is 0 unless otherwise specified
def sortname = params.sortname ?: "id" // Default is id, but could be any member of Thing that is not a "hasMany"
def sortorder = params.sortorder ?: "ASC" // Default is ASC, but could be DESC
def namedParams = [ obj: obj, max: max, offset: offset ]
Thing.executeQuery( "SELECT DISTINCT f.things FROM Foo f INNER JOIN f.things things INNER JOIN f.bars bars WHERE bars =:obj ORDER BY ${sortname} ${sortorder}", namedParams )
Hibernate不允许使用命名参数来指定ORDER BY
子句,所以我只是插入了字符串。问题是结果没有按照我指定的顺序排列。使用orderbyid
Grails告诉我id
是不明确的
知道变量sortname
将始终是Thing
的成员,如何指定排序依据?
我尝试过的一些事情:
ORDER BY Thing.id // Fail
ORDER BY f.things.id // Fail
ORDER BY things.id // FAIL!
查询应为:
SELECT DISTINCT thing FROM Foo f
INNER JOIN f.things thing
INNER JOIN f.bars bar
WHERE bar = :obj
ORDER BY thing.id
i、 e.您应该在select子句中使用实体的别名,而不是其路径,并在order by子句中使用相同的别名。!谢谢你的帮助。HQL与SQL并没有太大的不同,但它的不同足以给我带来一些问题。不过,我现在已经掌握得很好了:)