我对此有些困惑。 基本上，我想在LINQ to SQL中执行以下SQL查询：
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| SELECT f.*
FROM Foo f
WHERE f.FooId IN (
SELECT fb.FooId
FROM FooBar fb
WHERE fb.BarId = 1000
) |
任何帮助将不胜感激。
谢谢。
在LINQ to SQL中实现IN的一般方法
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| var q = FROM t1 IN table1
let t2s = FROM t2 IN table2
WHERE <Conditions FOR table2>
SELECT t2.KeyField
WHERE t2s.Contains(t1.KeyField)
SELECT t1; |
在LINQ to SQL中实现EXISTS的一般方法
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| var q = FROM t1 IN table1
let t2s = FROM t2 IN table2
WHERE <Conditions FOR table2>
SELECT t2.KeyField
WHERE t2s.Any(t1.KeyField)
SELECT t1; |
看看这篇文章。 基本上，如果要获得IN的等效值，则需要先构造一个内部查询，然后使用Contains()方法。 这是我的翻译尝试：
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| var innerQuery = FROM fb IN FoorBar WHERE fb.BarId = 1000 SELECT fb.FooId;
var RESULT = FROM f IN Foo WHERE innerQuery.Contains(f.FooId) SELECT f; |
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| FROM f IN Foo
WHERE f.FooID ==
(
FROM fb IN FooBar
WHERE fb.BarID == 1000
SELECT fb.FooID
)
SELECT f; |
尝试使用两个单独的步骤：
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| // CREATE a Dictionary / SET / Collection fids FIRST
var fids = (FROM fb IN FooBar
WHERE fb.BarID = 1000
SELECT NEW { fooID = fb.FooID, barID = fb.BarID })
.ToDictionary(x => x.fooID, x => x.barID);
FROM f IN Foo
WHERE fids.HasKey(f.FooId)
SELECT f |
//首先创建一个Dictionary / Set / Collection fids
查找其他关节炎
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| var fids = (FROM fb IN FooBar
WHERE fb.BarID = 1000
SELECT NEW { fooID = fb.FooID, barID = fb.BarID })
.ToDictionary(x => x.fooID, x => x.barID);
FROM f IN Foo
WHERE fids.HasKey(f.FooId)
SELECT f |
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| FROM f IN foo
WHERE f.FooID equals model.FooBar.SingleOrDefault(fBar => fBar.barID = 1000).FooID
SELECT NEW
{
f.Columns
}; |
//首先创建一个Dictionary / Set / Collection fids
查找其他关节炎
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| var fids = (FROM fb IN FooBar WHERE fb.BarID = 1000 SELECT NEW { fooID = fb.FooID, barID = fb.BarID }) .ToDictionary(x => x.fooID, x => x.barID);
FROM f IN Foo WHERE fids.HasKey(f.FooId) SELECT f |
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| var foos = Foo.Where
( f => FooBar.Where(fb.BarId == 1000).Select(fb => fb.FooId).Contains(f.FooId)); |
试试这个
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| var fooids = FROM fb IN foobar WHERE fb.BarId=1000 SELECT fb.fooID
var ff = FROM f IN foo WHERE f.FooID = fooids SELECT f |
