如何使用 LINQ 在多个 OR 内创建 SQL 嵌套 AND

发布于 2024-11-05 02:19:55 字数 347 浏览 0 评论 0原文

我正在尝试从下面的 SQL 示例创建等效的 LINQ 查询：

SELECT *
FROM FOO
WHERE 
    ((a == <val1>) AND (b == <val2>) AND (c == <val3>))
OR
    ((a == <val4>) AND (b == <val5>) AND (c == <val6>))

总会有 a、b 和 c 被 AND 组合在一起，并被 OR 包围。此模式可以出现 n 次。

我发现唯一可行的解决方案是使用 LINQ Union，但生成的 SQL 不是我想要的。

原文

I'm trying to create the equivelant LINQ query from the below SQL example:

SELECT *
FROM FOO
WHERE 
    ((a == <val1>) AND (b == <val2>) AND (c == <val3>))
OR
    ((a == <val4>) AND (b == <val5>) AND (c == <val6>))

There will always be an a, b, and c that will be AND'd together surrounded by an OR. This pattern can occur n amount of times.

The only solution I have found that work is using LINQ Union but the SQL generated isn't what I would like.

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女中豪杰 2024-11-12 02:19:55

尝试实现 PredicateBuilder 类。

那么也许你可以使用这样的东西：

var pred = PredicateBuilder.False<Foo>();

foreach(var criteria in myCriteriaSet)
{            
    pred = pred.Or(x => x.ID== criteria.ID && 
                        x.Name== criteria.Name &&
                        x.Created == criteria.SomeDate);
}

var matching = db.Foos.Where(pred);

然后假设你的标准是可枚举的。根据需要进行修改以满足您的需求。

Try implementing the PredicateBuilder class.

Then perhaps you can use something like this:

var pred = PredicateBuilder.False<Foo>();

foreach(var criteria in myCriteriaSet)
{            
    pred = pred.Or(x => x.ID== criteria.ID && 
                        x.Name== criteria.Name &&
                        x.Created == criteria.SomeDate);
}

var matching = db.Foos.Where(pred);

This then assumes your criteria is enumerable. Modify as you need to accommodate your needs.

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ㄖ落Θ余辉 2024-11-12 02:19:55

您可以制作一个很长的条件语句：

var foo = from f in db.Foos.Where((f => f.A == val1 && f.b == val2 && f.c == val3) ||
                                  (f => f.A == val4 && f.b == val5 && f.c == val6))

或者，在我看来，哪个更好：

var predicate = PredicateBuilder.False<Foo>();
predicate = predicate.Or(f => f.A == val1 && f.A == val2 && f.A == val3);
predicate = predicate.Or(f => f.A == val4 && f.A == val5 && f.A == val6);
var foo = db.Foos.Where(predicate);

这些也可以是有条件的：

var predicate = PredicateBuilder.False<Foo>();
predicate = predicate.Or(f => f.A == val1 && f.A == val2 && f.A == val3);
if (condition)
    predicate = predicate.Or(f => f.A == val4 && f.A == val5 && f.A == val6);
var foo = db.Foos.Where(predicate);

You can make a long conditional statement:

var foo = from f in db.Foos.Where((f => f.A == val1 && f.b == val2 && f.c == val3) ||
                                  (f => f.A == val4 && f.b == val5 && f.c == val6))

Or, which is preferable IMO:

var predicate = PredicateBuilder.False<Foo>();
predicate = predicate.Or(f => f.A == val1 && f.A == val2 && f.A == val3);
predicate = predicate.Or(f => f.A == val4 && f.A == val5 && f.A == val6);
var foo = db.Foos.Where(predicate);

These can be conditional also:

var predicate = PredicateBuilder.False<Foo>();
predicate = predicate.Or(f => f.A == val1 && f.A == val2 && f.A == val3);
if (condition)
    predicate = predicate.Or(f => f.A == val4 && f.A == val5 && f.A == val6);
var foo = db.Foos.Where(predicate);

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