我正在使用NHibernate 2.0,当我提交请求返回前2条记录的请求时,我在SQL中获得了许多ORDER BY子句。当我取出Max结果时,查询看起来很好(没有ORDER BY语句)。为什么NHibernate会在寻找记录子集时自动添加它?提前致谢
请参阅下面的SQL语句:
意外的ORDER BY
exec sp_executesql N'SELECT TOP 2 Person1_36_0_, LastReco2_36_0_, SSN3_36_0_, FirstName4_36_0_, LastName5_36_0_, MiddleIn6_36_0_, Title7_36_0_, Suffix8_36_0_, DateOfBi9_36_0_, IsDeceased10_36_0_, Decease11_36_0_, Contact12_36_0_, MailHol13_36_0_, MailHol14_36_0_, MailHol15_36_0_, Preferr16_36_0_, CreatedBy17_36_0_, Created18_36_0_, ModifiedBy19_36_0_, Modifie20_36_0_ FROM (SELECT ROW_NUMBER() OVER(ORDER BY __hibernate_sort_expr_0__) as row, query.Person1_36_0_, query.LastReco2_36_0_, query.SSN3_36_0_, query.FirstName4_36_0_, query.LastName5_36_0_, query.MiddleIn6_36_0_, query.Title7_36_0_, query.Suffix8_36_0_, query.DateOfBi9_36_0_, query.IsDeceased10_36_0_, query.Decease11_36_0_, query.Contact12_36_0_, query.MailHol13_36_0_, query.MailHol14_36_0_, query.MailHol15_36_0_, query.Preferr16_36_0_, query.CreatedBy17_36_0_, query.Created18_36_0_, query.ModifiedBy19_36_0_, query.Modifie20_36_0_, query.__hibernate_sort_expr_0__ FROM (SELECT this_.Person_id as Person1_36_0_, this_.[LastRecordVersion] as LastReco2_36_0_, this_.[SSN] as SSN3_36_0_, this_.[FirstName] as FirstName4_36_0_, this_.[LastName] as LastName5_36_0_, this_.[MiddleInitial] as MiddleIn6_36_0_, this_.[Title] as Title7_36_0_, this_.[Suffix] as Suffix8_36_0_, this_.[DateOfBirth] as DateOfBi9_36_0_, this_.[IsDeceased] as IsDeceased10_36_0_, this_.[DeceasedDate] as Decease11_36_0_, this_.[ContactMethod_id] as Contact12_36_0_, this_.[MailHoldReason_id] as MailHol13_36_0_, this_.[MailHoldStartDate] as MailHol14_36_0_, this_.[MailHoldEndDate] as MailHol15_36_0_, this_.[PreferredName] as Preferr16_36_0_, this_.[CreatedBy] as CreatedBy17_36_0_, this_.[CreatedDate] as Created18_36_0_, this_.[ModifiedBy] as ModifiedBy19_36_0_, this_.[ModifiedDate] as Modifie20_36_0_, CURRENT_TIMESTAMP as __hibernate_sort_expr_0__ FROM MC_Person this_ WHERE this_.[SSN] = @p0) query) page WHERE **page.row > 0 ORDER BY __hibernate_sort_expr_0__**', N'@p0 nvarchar(9)',@p0=N'123456789'
更正SQL(未获得前2条记录)
exec sp_executesql N'SELECT this_.Person_id as Person1_36_0_, this_.[LastRecordVersion] as LastReco2_36_0_, this_.[SSN] as SSN3_36_0_, this_.[FirstName] as FirstName4_36_0_, this_.[LastName] as LastName5_36_0_, this_.[MiddleInitial] as MiddleIn6_36_0_, this_.[Title] as Title7_36_0_, this_.[Suffix] as Suffix8_36_0_, this_.[DateOfBirth] as DateOfBi9_36_0_, this_.[IsDeceased] as IsDeceased10_36_0_, this_.[DeceasedDate] as Decease11_36_0_, this_.[ContactMethod_id] as Contact12_36_0_, this_.[MailHoldReason_id] as MailHol13_36_0_, this_.[MailHoldStartDate] as MailHol14_36_0_, this_.[MailHoldEndDate] as MailHol15_36_0_, this_.[PreferredName] as Preferr16_36_0_, this_.[CreatedBy] as CreatedBy17_36_0_, this_.[CreatedDate] as Created18_36_0_, this_.[ModifiedBy] as ModifiedBy19_36_0_, this_.[ModifiedDate] as Modifie20_36_0_ FROM MC_Person this_ WHERE this_.[SSN] = @p0', N'@p0 nvarchar(9)',@p0=N'123456789'
答案 0 :(得分:1)
这是实现分页的方式。因此,只有前n个元素没有特殊情况,因为例如Oracle不支持这种结构。
所以任何设置了分页限制的东西都是这样做的。
你得到了正确的结果吗?
答案 1 :(得分:0)
如果没有排序,最高选择没有多大意义,因为订购可能会因数据库表的维护而改变。
难道你不知道如何定义你想要的前两种结果?因此顺序由?