如何在LINQ中做GroupBy多列
SQL中类似的代码:
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
当前回答
对于VB和匿名/lambda:
query.GroupBy(Function(x) New With {Key x.Field1, Key x.Field2, Key x.FieldN })
其他回答
对于VB和匿名/lambda:
query.GroupBy(Function(x) New With {Key x.Field1, Key x.Field2, Key x.FieldN })
程序样例:
.GroupBy(x => new { x.Column1, x.Column2 })
好的，这个是:
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();
.GroupBy(x => x.Column1 + " " + x.Column2)
从c# 7开始，你也可以使用值元组:
group x by (x.Column1, x.Column2)
or
.GroupBy(x => (x.Column1, x.Column2))
