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c# - 协助将我的 SQL 查询转换为 LINQ？

问题描述

我需要一些帮助来将此查询转换为 LINQ：

SELECT
    st.ProductId, st.ProductType, st.StockValue, st.InOut, st.SupplierCmdId, st.CreationDate,
    (SELECT su.Id FROM Suppliers AS su 
     WHERE su.Id = (SELECT suo.SupplierId FROM SupplierOrders AS suo 
                    WHERE suo.Id = st.SupplierCmdId)) AS SupplerId
FROM 
    StockDetails AS st 
WHERE 
    st.ProductType = 'Yarn' 
    AND st.ProductId = 2835 
ORDER BY 
    st.CreationDate DESC

输出：

ProductId   ProductType StockValue  InOut   SupplierCmdId   CreationDate                SupplerId
2835        Yarn        10          1       1450            2020-03-12 15:25:54.000     151
2835        Yarn        5           0       NULL            2019-03-04 00:00:00.000     NULL
2835        Yarn        5           0       NULL            2018-12-23 00:00:00.000     NULL
2835        Yarn        10          1       1398            2018-12-17 10:51:17.000     151

提前致谢

我努力了：

var ProductType = "Yarn";
var ProductId = 2835;

stocks = (from st in _context.StockDetails
join sn in _context.StockStatus on st.StatusId equals sn.Id
where st.ProductId == ProductId 
      && st.ProductType == ProductType 
orderby st.CreationDate descending
select new StockList
    {
    StockValue = st.StockValue,
    InOut = st.InOut,
    SupplierCmdId = st.SupplierCmdId,
    CreationDate = st.CreationDate
    });

在此我需要找到供应商 ID（请参阅 SQL 查询）

标签： c#sqllinq

解决方案

我相信这应该是等价的：

var productType = "Yarn";
var productId = 2835;
var query =
    from st in ctx.StockDetails
    where st.ProductType == productType
    where st.ProductId == productId
    orderby st.CreationDate descending
    let suppliers =
        from suo in ctx.SupplierOrders
        join su in ctx.Suppliers on suo.SupplierId equals su.Id
        where suo.Id == st.SupplierCmdId
        select su
    from su in suppliers.DefaultIfEmpty()
    select new
    {
        st.ProductId,
        st.ProductType,
        st.StockValue,
        st.InOut,
        st.SupplierCmdId,
        st.CreationDate,
        SupplierId = su.Id,
    };

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