如何在Where 子句中获得OR？

发布于 2024-07-24 09:36:39 字数 312 浏览 8 评论 0原文

我正在构建一个临时查询以发送到 SQL，执行以下操作：

var data = from d in db.xxxx select d;
foreach (pattern in user_stuff)
   data = data.Where(d=>SqlMethods.Like(d.item,pattern)==true);

问题是 WHERE 子句 AND 组合在一起。我需要OR。

知道如何获得OR吗？

原文

I'm building an ad-hoc query to send to SQL doing the following:

var data = from d in db.xxxx select d;
foreach (pattern in user_stuff)
   data = data.Where(d=>SqlMethods.Like(d.item,pattern)==true);

The problem is that the WHERE clauses get AND'ed together. I need OR's.

Any idea how to get an OR?

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执笏见 2024-07-31 09:36:39

我回答我自己的问题怎么样：
PredicateBuilder

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和影子一齐双人舞 2024-07-31 09:36:39

您需要构造一个表达式来表示复合 OR 谓词，然后将其传递给Where：

var data = from d in db.xxxx select d;
Expression<Func<Data, bool>> predicate = null;
foreach (var pattern in user_stuff)
{
    Expression<Func<Data, bool>> newPredicate = d => SqlMethods.Like(d..item, pattern));
    if (predicate == null) predicate = newPredicate;
    else predicate = Expression.OrElse(predicate, newPredicate);
}
return data.Where(predicate);

编辑：这可能就是 PredicateBuilder 所做的，只是更混乱:)

You need to construct an Expression to represent the composite OR predicate, then pass that to Where:

var data = from d in db.xxxx select d;
Expression<Func<Data, bool>> predicate = null;
foreach (var pattern in user_stuff)
{
    Expression<Func<Data, bool>> newPredicate = d => SqlMethods.Like(d..item, pattern));
    if (predicate == null) predicate = newPredicate;
    else predicate = Expression.OrElse(predicate, newPredicate);
}
return data.Where(predicate);

EDIT: This is probably what PredicateBuilder does, only a lot messier :)

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