SQL到LINQ的翻译

Question

SELECT * FROM Recipe WHERE ID IN 
    (SELECT RID FROM Recipe_Ingredient WHERE IID IN 
           (SELECT MIN(ID) FROM Ingredients WHERE Name IN('broccoli','egg')))

我正在尝试将此sql查询转换为linq。到目前为止，我没有运气。

我收到了一系列成分。到目前为止，我得到了这个：

List<string> searchList = new List<string>(search);
var ing = context.Ingredients.Where(x => x.Name.Contains(searchList.ToString())).ToList();
var recing = context.Recipe_Ingredients.Where(x => ing.Contains(x.IID)).Select(x => x.IID).ToList();
var rec = context.Recipes.Where(x => recing.Contains(x.ID)).ToList();

但是通过使用调试器，它在ing上失败了，因为searchList x.Name（searchList[0] = 'egg'当我用它进行测试时不包含）

Answer 1

你在线上犯了小错误。前2个ToList方法是多余的。

List<string> searchList = new List<string>(search);
var ing = context.Ingredients.Where(x => searchList.Contains(x.Name));
var recing = context.Recipe_Ingredients.Where(x => ing.Contains(x.IID)).Select(x => x.IID);
var rec = context.Recipes.Where(x => recing.Contains(x.ID)).ToList();

Answer 2

您没有翻译SQL中的MIN(...)。

var searchList = new List<string>(search); // broccoli, egg
var recipies = context.Recipes
    .Where(r =>
        context.Recipe_Ingredients
            .Where(ri =>
                context.Ingredients
                    .Where(i => searchList.Contains(i.Name))
                    .Select(i => i.ID)
                    .Min() == ri.IID
            )
            .Select(ri => ri.RID)
        .Contains(r.ID)
    )
    .ToList();

Answer 3

1. 您反转包含（您未执行条款）
2. Min（Id）不能是一个列表（在你的sql查询中），它将是一个唯一的id。
3. 过早放置ToList()，会产生多个查询。

所以要靠近你的代码，你可以做到

List<string> searchList = new List<string>(search);
var ingId = context.Ingredients.Where(x => searchList.Contains(x.Name)).Min(m => m.Id);
var recing = context.Recipe_Ingredients.Where(x => x.IID == ingId).Select(x => x.RID);
var rec = context.Recipes.Where(x => recing.Contains(x.ID)).ToList();