Question

如何将此查询转换为实体框架查询？

select Price,
(
    select Cost.Title 
    from Cost 
    where Cost.CostID= CostItem.CostID
) as nameCost
from CostItem 
where ItemID= 11

Answer 1

您的查询也可以使用LEFT JOIN：

编写

SELECT
    ci.Price,
    NameCost = c.Title
FROM CostItem ci
LEFT JOIN Cost c
    ON c.CostID = ci.CostID
WHERE ci.ItemID = 11

使用C＃将其转换为Linq，您得到：

var t =
    from ci in CostItem
    join c in Cost on ci.CostID equals c.CostID into lc
    from c in lc.DefaultIfEmpty()
    where ci.ItemID == 11
    select new {
        Price = ci.Price,
        NameCost = c.Title
    };

Answer 2

var result = dbContext.CostItems
    .Where(item => item.ItemId == 11)
    .Select(item => new { Price = item.Price, nameCose = item.Cost.Title })

确保您在实体对象中正确设置了关系

将SQL查询转换为EntityFramework

2 个答案: