Question

I m试图将以下T-SQL问题转换为linq2sql。无论我做什么,它还是把它转化为一些新生事物,并加入其中。任何建议?

表A、B、C

SELECT A.Id, A.Name, Pool.Total
FROM A
INNER JOIN B ON A.Id = B.AId
LEFT JOIN (
SELECT AId,
SUM(Quantity) as Total
FROM C 
GROUP BY AId) AS Pool ON A.Id = C.AId
WHERE Pool.Total < B.Threshold

Answer 1

我写了一份准则调查表,它的确向佩雷斯翻译,但execution plan看上去,批次中的查询费用为50/50,因此,翻译的询问是相同的(或是同义词)。

The linq query is

from a in As 
join b in Bs on a.ID equals b.AID 
join  pool in (from c in Cs
                group c by c.AId into cG
                select new {AID = cG.Key,Total = cG.Sum(c=>c.Quantity)} ) on a.ID equals pool.AID into poolG
from pool in poolG.DefaultIfEmpty()
where pool.Total<b.Threshold 
select new {a.ID, a.Name, pool.Total}

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