Question

请 - 我有这个SQL语句：

SELECT FK_ClassId, LectureDays
FROM tbl_TimeTables
WHERE Term = 'First Term' 
  AND FK_session = 4 
  AND fk_classId = 1 
  AND (fk_subjectid <> 1)
GROUP BY FK_classId, LectureDays
HAVING (COUNT(*) < 6)

返回此结果：

Image Embedded Here, giving the right result

但是当我向linq解释时，我得到了不同的结果：

Tbl_TimeTables.GroupBy(x => new { x.FK_Session, x.Term, x.LectureDays,   
x.FK_ClassId, x.FK_SubjectId })
.Where(grp => grp.Count() < 6 && grp.Key.FK_Session == 4 && grp.Key.Term ==   
"First Term" && grp.Key.FK_ClassId == 1 && grp.Key.FK_SubjectId != 1)
.Select(grp => new 
{
  LectureDay = grp.Key.LectureDays,
  ClassId = grp.Key.FK_ClassId
})

Wrong Results Picture Link here

请查看我的代码，我做错了什么？

由于

添

Answer 1

根据Matt Gibson的建议，这是linq查询的正确方法：

Tbl_TimeTables
.Where(x => x.FK_Session == 4 && x.Term == "First Term" && x.FK_ClassId == 1   
&& x.FK_SubjectId != 1)
.GroupBy(x => new { x.FK_ClassId, x.LectureDays })
.Where(grp => grp.Count() < 6)
.Select(grp => new 
{
  ClassId = grp.Key.FK_ClassId,
  LectureDay = grp.Key.LectureDays
})

这与sql完全一样还要指出这个链接：http://www.dotnettricks.com/learn/sqlserver/definition-use-of-group-by-and-having-clause帮助我理解了语句的工作方式，这有助于了解Matt在说什么。

解释Sql的位置和对linq的语句给出不同的结果

1 个答案: