select ...,(b.quantity-isnull(sum(c.quantity),0))*b.unit_price as totalprice from table b left join table2 c on ... where ... group by ...

WITH tb AS
(
select ...,(b.quantity-isnull(sum(c.quantity),0))*b.unit_price as totalprice from table b left join table2 c on ... where ... group by ...
)
SELECT SUM(totalprice )
FROM tb

------解决方案--------------------

探讨

如下代码

SQL code

select ...,(b.quantity-isnull(sum(c.quantity),0))*b.unit_price as totalprice from table b left join table2 c on ... where ... group by ...



以上代码的查询结果 totalprice 列的值,需要全部值累加起来……


------解决方案--------------------
子查询算不算一次出来？
子查询与with类似了

另外，不使用group，直接sum就是你要的结果了

------解决方案--------------------
with是mssql2005才开始的，专有的