实体Linq中两列的总和

Question

我正在努力将查询从sql转换为实体linq。我的选择应该是prodhis.stock_units_free的总和减去prodhis.stock_units_it的总和

有人能指出我正确的方向吗？

这就是我所拥有的

Dim res As Integer = (From it In rmis.product_detail Join prodhis In rmis.PRODUCT_HISTORY On it.SKU_ID Equals prodhis.SKU_ID _
                         Where prodhis.WEEK_SELECTOR = cws AndAlso
                         it.POS_CODE = ItemID AndAlso
                         prodhis.BRANCH_ID = 23
                         'Stuck Here:
Select (sum(prodhis.STOCK_UNITS_FREE) - sum(prodhis.STOCK_UNITS_IT))

Sum未声明错误....

由于

Answer 1

将您的选择更改为：

Select prodhis.STOCK_UNITS_FREE - prodhis.STOCK_UNITS_IT).Sum();