带限制的投影。交换接口

Question

带有Restrictions.Discjunction（）或Restrictions.Or（）的投影将产生WHERE子句而不是HAVING子句。这将导致错误（WHERE子句不能引用聚合表达式）。

例子：

.CreateCriteria(typeof(SalesOrderLine), "SOL") 
.CreateCriteria("DeliveryOrderLines", "DOL", JoinType.LeftOuterJoin) 
.SetProjection(
    Projections.GroupProperty("SOL.Key").As("SalesOrderLineId"), 
    Projections.GroupProperty("SOL.Item"), 
    Projections.GroupProperty("SOL.Description"), 
    Projections.GroupProperty("SOL.UnitPrice"), 
    Projections.GroupProperty("SOL.Quantity"), 
    Projections.GroupProperty("SOL.DiscountPercentage"), 
    Projections.GroupProperty("SOL.SalesOrder")) 
.Add(Restrictions.Or(
    Restrictions.IsNull(Projections.Sum("DOL.Quantity")), 
    Restrictions.GtProperty("SOL.Quantity", Projections.Sum("DOL.Quantity")))), 
.List(); 

SQL结果：

SELECT this_.SalesOrderLineId as y0_, this_.Item as y1_, this_.Description as y2_, this_.UnitPrice as y3_, this_.Quantity as y4_, this_.DiscountPercentage as y5_, this_.SalesOrderId as y6_ FROM SalesOrderLine this_ left outer join DeliveryOrderLine dol1_ on this_.SalesOrderLineId=dol1_.SalesOrderLineId 
WHERE (sum(dol1_.Quantity) is null or this_.Quantity > sum(dol1_.Quantity)) 
GROUP BY this_.SalesOrderLineId, this_.Item, this_.Description, this_.UnitPrice, this_.Quantity, this_.DiscountPercentage, this_.SalesOrderId 

难道我做错了？或者这是Nhibernate 3.1中的一个错误？

在此先感谢:)。

Answer 1

上次我检查了HAVING子句不被Criteria API支持。您需要使用支持HAVING的HQL。

要使用标准的API使用，你就必须修改您的查询到这一点：

SELECT this_.SalesOrderLineId as y0_, this_.Item as y1_, this_.Description as y2_, this_.UnitPrice as y3_, this_.Quantity as y4_, this_.DiscountPercentage as y5_, this_.SalesOrderId as y6_ FROM SalesOrderLine this_ left outer join DeliveryOrderLine dol1_ on this_.SalesOrderLineId=dol1_.SalesOrderLineId 
WHERE (select sum(Quantity) from DeliveryOrderLine) is null or (select sum(Quantity) from > SalesOrderLine) > (select sum(Quantity) from DeliveryOrderLine) 
GROUP BY this_.SalesOrderLineId, this_.Item, this_.Description, this_.UnitPrice, this_.Quantity, this_.DiscountPercentage, this_.SalesOrderId 

，我已经给会因为多次和计算的一些性能问题的解决方案，但它会得到工作完成。

你也可以试试这个，但我不知道这是否会正常运行：

SELECT this_.SalesOrderLineId as y0_, this_.Item as y1_, this_.Description as y2_, this_.UnitPrice as y3_, this_.Quantity as y4_, this_.DiscountPercentage as y5_, this_.SalesOrderId as y6_, SUM(dol1_Quantity) as sum1, SUM(this_.Quantity) as sum2 from SalesOrderLine this_ left outer join DeliveryOrderLine dol1_ on this_.SalesOrderLineId=dol1_.SalesOrderLineId 
WHERE sum1 is null or sum1 > sum2 
GROUP BY this_.SalesOrderLineId, this_.Item, this_.Description, this_.UnitPrice, this_.Quantity, this_.DiscountPercentage, this_.SalesOrderId 

希望这有助于！