如何遍历列表构建LINQ查询？解决查询无法翻译报错

我有一段可正常运行的LINQ查询：

posts.Where(post =>
    post.Fields
        .Where(x =>
            x.RegionId == "RecipeArticleDetails" &&
            (x.FieldId == "RecipePrepTime" || x.FieldId == "RecipeCookTime")
        )
        .GroupBy(x => x.PostId)
        .Select(x => new { ID = x.Key, Value = x.Sum(y => Convert.ToInt32(y.Value)) })
        .Where(x => x.Value > 10 && x.Value < 40)
        .Any()
)
List<string> suppliedTimes = new List<string>(){
    "10-60","0-10"
};

我想把其中的Where(x => x.Value > 10 && x.Value < 40)替换成从suppliedTimes列表读取的时间范围筛选条件，尝试了以下代码却报错：

posts.Where(post =>
    suppliedTimes.Select(x => new {low = Convert.ToInt32(x.Split("-",StringSplitOptions.RemoveEmptyEntries)[0]), high = Convert.ToInt32(x.Split("-",StringSplitOptions.RemoveEmptyEntries)[1]) })
    .Any( a =>
        post.Fields
            .Where(x =>
                x.RegionId == "RecipeArticleDetails" &&
                (x.FieldId == "RecipePrepTime" || x.FieldId == "RecipeCookTime")
            )
            .GroupBy(x => x.PostId)
            .Select(x => new { ID = x.Key, Value = x.Sum(y => Convert.ToInt32(y.Value)) })
            .Where(x => x.Value > a.low && x.Value < a.high)
            .Any()
        )
)

报错信息：

could not be translated. Either rewrite the query in a form that can be translated, or switch to client evaluation explicitly by inserting a call to 'AsEnumerable', 'AsAsyncEnumerable', 'ToList', or 'ToListAsync'.

• EF Core无法将suppliedTimes.Select(...)里的客户端操作（字符串Split、Convert.ToInt32类型转换）翻译成SQL语句，这类内存中的逻辑没有对应的数据库执行逻辑。
• 嵌套的Any结合动态生成的范围对象，导致查询结构过于复杂，ORM无法解析为合法的数据库查询语句。

核心思路是提前在客户端解析时间范围，避免在EF Core查询中执行无法翻译的操作，再将多范围筛选转化为数据库可识别的逻辑。

步骤1：预解析时间范围 #

先把suppliedTimes的字符串格式转换成整数范围列表，放在客户端内存中：

var timeRanges = suppliedTimes
    .Select(s => 
    {
        var parts = s.Split("-", StringSplitOptions.RemoveEmptyEntries);
        return new { Low = int.Parse(parts[0]), High = int.Parse(parts[1]) };
    })
    .ToList();

步骤2：重构LINQ查询 #

方法一：简化嵌套Any逻辑

将多范围筛选直接合并到统计后的时间判断中：

var filteredPosts = posts
    .Where(post =>
        post.Fields
            .Where(x =>
                x.RegionId == "RecipeArticleDetails" &&
                (x.FieldId == "RecipePrepTime" || x.FieldId == "RecipeCookTime")
            )
            .GroupBy(x => x.PostId)
            .Select(g => g.Sum(y => Convert.ToInt32(y.Value)))
            .Any(totalTime => 
                timeRanges.Any(r => totalTime > r.Low && totalTime < r.High)
            )
    );

方法二：构建表达式树生成OR条件（适配复杂场景）

如果方法一仍有翻译问题，可以手动构建表达式树，把多个范围条件合并成OR逻辑，让EF Core能生成对应的SQL：

// 初始化基础条件为false
Expression<Func<int, bool>> rangeCondition = t => false;
foreach (var range in timeRanges)
{
    var currentRange = range;
    // 单个范围的条件表达式
    Expression<Func<int, bool>> currentCondition = t => t > currentRange.Low && t < currentRange.High;
    // 合并为OR逻辑
    rangeCondition = Expression.Lambda<Func<int, bool>>(
        Expression.OrElse(rangeCondition.Body, currentCondition.Body),
        rangeCondition.Parameters
    );
}

// 应用到最终查询
var filteredPosts = posts
    .Where(post =>
        post.Fields
            .Where(x =>
                x.RegionId == "RecipeArticleDetails" &&
                (x.FieldId == "RecipePrepTime" || x.FieldId == "RecipeCookTime")
            )
            .GroupBy(x => x.PostId)
            .Select(g => g.Sum(y => Convert.ToInt32(y.Value)))
            .Any(rangeCondition)
    );

内容的提问来源于stack exchange，提问作者atoms