有一表A,字段为:客户,数量1,数量2;想使用SQLCommand语句,求出 Sum(数量1)-SUM(数量2 )
我写代码如下:
Dim cmd As New SQLCommandDim dt As DataTablecmd.CommandText = "SELECT DISTINCT 客户,数量1,数量2,数量1-数量2 As 余额 From {A}"dt = cmd.ExecuteReader()
或者
Dim val As IntegerDim cmd As New SQLCommandcmd.CommandText = "Select 客户,Sum(数量1)-Sum(数量2) From {A} "val = cmd.ExecuteScalar()
这两种代码运行后都不能计算出正确的余额(余额都为0)