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如何在 LINQ 中执行 GroupBy 多列

SQL 中与此类似的东西：

SELECT * FROM <TableName> GROUP BY <Column1>,<Column2>

如何将其转换为 LINQ：

QuantityBreakdown
(
    MaterialID int,
    ProductID int,
    Quantity float
)

INSERT INTO @QuantityBreakdown (MaterialID, ProductID, Quantity)
SELECT MaterialID, ProductID, SUM(Quantity)
FROM @Transactions
GROUP BY MaterialID, ProductID

使用匿名类型。

例如

group x by new { x.Column1, x.Column2 }

程序样本

.GroupBy(x => new { x.Column1, x.Column2 })

好吧得到这个：

var query = (from t in Transactions
             group t by new {t.MaterialID, t.ProductID}
             into grp
                    select new
                    {
                        grp.Key.MaterialID,
                        grp.Key.ProductID,
                        Quantity = grp.Sum(t => t.Quantity)
                    }).ToList();