具有 CASE 和子查询的 sql to LINQ

Question

我一直在努力将下面的查询转换为 linq 查询，我非常接近，但我不确定如何将 case 语句添加到 LINQ。谷歌搜索让我如此接近。

原始工作查询：

SELECT *, CASE
    WHEN Recipe_Name IN (SELECT Recipe_Name FROM Recipes WHERE Status = 2) THEN 0
    ELSE 1 
END AS editable
FROM Recipes WHERE Status = 1 ORDER BY Recipe_Name;

我的 LINQ - 缺少案例陈述：

var lcrecipes = from r in db.Recipes where r.Status == 2 select r.Recipe_Name;
            var RecipeResults = from rr in db.Recipes where lcrecipes.Contains(rr.Recipe_Name) select rr;

我也试过了：

var RecipeResults = from rr in db.Recipes
                                   where lcrecipes.Contains(rr.Recipe_Name)
                                   select new
                                   {
                                       editable = rr.Status == 2 ? "false" :
                                                   rr.Status == 1 ? "true" : ""
                                   };

如何将 case 语句合并到 LINQ 中？任何朝着正确方向的推动将不胜感激

Answer 1

想一想！

可编辑菜谱的状态不等于 2，因此下面的查询仅返回可编辑菜谱，满足您的需求；）您不需要任何子查询；）

var editablerecipes = from r in db.Recipes
    where r.Status != 2
    order r by r.Recipe_Name
    select r.Recipe_Name;

如果您想添加可编辑字段，请使用：

var recipesWithEditableFlag = from r in db.Recipes
    order r by r.Recipe_Name
    select new {RecipeName= r.Recipe_Name, Editable = r.Status==2 ? "no" : "yes"};

对应的 SQL 应该如下所示：

SELECT Recipe_Name, CASE WHEN Status = 2 THEN 'no' ELSE 'yes' END AS editable
FROM Recipes
ORDER BY Recipe_Name;