如何简化Where(e => e.prop1.contains()|| e.prop2.contains()|| ...)中的重复OR条件 [英] How to simplify repetitive OR condition in Where(e => e.prop1.contains() || e.prop2.contains() || ...)

问题描述

我有很多这样的代码:

IQueryable<MyEntity> query...
query.Where(e => EF.Functions.Like(e.Property1,  pattern)
                || EF.Functions.Like(e.Property2, pattern)
                || EF.Functions.Like(e.Property3, pattern)
                ...);

如何简化它以将重复代码删除为类似这样的内容:

How can I simplify it to remove the repetitive code to something like this:

query.Where(Search(pattern, e => e.Property1, e => e.Property2, e => e.Property3));  

或

query.Where(e => Search(pattern, e.Property1,  e.Property2,  e.Property3))  

查询必须通过EF转换为SQL，因此where条件不能只是任何返回布尔值的函数.它必须是可翻译的Expression< Func< TEntity，bool>>

The query must be translated to SQL by EF, so the where condition can't be just any function that return boolean. It must be translatable Expression<Func<TEntity, bool>>

推荐答案

您可以将其重写以将所有属性组合到一个数组中，并检查是否匹配:

You can rewrite it to combine all the properties into an array and check that for a match:

query.Where(e =>
    new[]{ e.Property1, e.Property2, e.Property3}
      .Any(p => EF.Functions.Like(p, pattern) )
);

等效的SQL是:

WHERE EXISTS (SELECT 1
    FROM (VALUES
      (e.Property1),
      (e.Property2),
      (e.Property3)
    ) v(Prop)
    WHERE v.Prop LIKE @pattern
)

---

等效的&&/AND 语义略有不同:

query.Where(e =>
    new[]{ e.Property1, e.Property2, e.Property3}
      .All(p => EF.Functions.Like(p, pattern) )
);

等效的SQL是双负数:

The equivalent SQL is a double-negative:

WHERE NOT EXISTS (SELECT 1
    FROM (VALUES
      (e.Property1),
      (e.Property2),
      (e.Property3)
    ) v(Prop)
    WHERE v.Prop NOT LIKE @pattern
)

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