Question

我有以下SQL语句

SELECT D.*, COALESCE(T_DIZ.adet, 0) AS DIZ, COALESCE(T_OMU.adet, 0) as OMUZ
FROM

(SELECT A.DOK,COUNT(DISTINCT GNL) AS toplam FROM CKS A GROUP BY A.DOK ) AS D

LEFT OUTER JOIN (
    SELECT DOK, ATUR,count(DISTINCT HST)as Adet, COUNT(DISTINCT GNL) AS adet FROM CKS
    WHERE ATUR LIKE '%DIZ%'
    GROUP BY DOK, ATUR  
) T_DIZ ON(T_DIZ.DOK = D.DOK)

LEFT OUTER JOIN (
    SELECT DOK, ATUR,count(DISTINCT HST)as Adet, COUNT(DISTINCT GNL) AS adet FROM CKS
    WHERE ATUR LIKE '%OMU%'
    GROUP BY DOK, ATUR  
) T_OMU ON(T_OMU.DOK = D.DOK)

此查询结果相同

SELECT DISTINCT(DOK), (COUNT(DISTINCT GNL) ) AS TOP,
 (CASE WHEN ATUR LIKE '%DIZ%' THEN COUNT(DISTINCT GNL) ELSE 0 END) AS DIZ,
 (CASE WHEN ATUR LIKE '%OMU%' THEN COUNT(DISTINCT GNL) ELSE 0 END) AS OMU
FROM S_GC_UST
WHERE GC = 'C'
GROUP BY DOK, ATUR, TRH

有人可以帮助我将此声明转换为LINQ吗？

谢谢。

Answer 1

您的SQL查询非常困难，我无法为您提供完整的解决方案。我不得不给你一些想法，将这个复杂的SQL查询拆分成可以轻松处理的小查询。

你有三个部分，我简化为D，T_DIZ，T_OMU。

然后我必须分别简化它们。在得到查询的方案图后，你应该更好地考虑Groupby，Coalesce，LEFT OUTER JOIN。

我们分别有三个查询，如query1，query2，query3。

query1 = from a in CKS Group a by Key DOK into Group
         select DOK = Group.DOK, 
                TOPLAM = Group.Select(x => x.GNL).Distinct().Count()

query2 = from b in CKS 
         where SqlMethods.Like(b.ATUR, "%DIZ%")
         Group b by new Key {DOK, ATUR } into Group 
         select DOK  = Group.DOK, 
                ATUR = Group.ATUR,
                Adet = Group.Select(x => x.HST).Distinct().Count(),
                adet = Group.Select(x => x.GNL).Distinct().Count()

//the same way of query2, you can get query3. 

//Then you can use a query23 to unit all of query2 and query3 
query23 = (from x in query2 select new {DIZ= x.A, OMUZ = 0})
          .Concat( from y in query3  select new {DIZ = 0, DIZ = y.B} );

//At last, you can put query1 and query23 together.
query123 = from e in query1  
           join f in query23 
           on e.DOK equals f.DOK  
           into query
           from g in query.DefaultIfEmpty()
           select new { toplam = g.toplam , 
                        DIZ= g==null ? 0:g.DIZ ,
                        OMUZ = g==null?0:g.OMUZ   };

//and then 
var result = query123.ToList().

由于时间原因，解决方案仍有一些小缺点。希望这对你有所帮助。

Answer 2

简单的答案是你没有，至少以一种高效的方式假设你使用实体框架或类似的ORM。

This post描述了如何处理LINQ中的子查询。据我所知，没有可能的方法在＆＃34;语义＆＃34; LINQ。该帖子中建议的方法的问题是子查询不会与主查询一起执行，并且性能是一场噩梦。

我总是通过在T-SQL中编写存储过程并通过EF映射来处理这种情况。

如何将此SQL查询转换为LINQ查询？

2 个答案: