没做索引,T1:purchases(采购单,品名,数量)T2:storehouse(送货单,品名,数量,采购单)
比如创建了采购单CG001,纸箱,1000 CG002,木板,500 ,供应商只发运了GC001的纸箱600,如果我想查询采购订单完成情况,应该怎么写?select * from purchases INNER JOIN
storehouse ON purchases.采购单 = dbo.storehouse.采购单
CG002因为还没进仓所以没有显示,感觉跟where purchases.采购单 = dbo.storehouse.采购单一个效果...我要把还没进仓的都显示出来,又不想创建时插入storehouse,因为送货单跟采购单是多对一,求教……
比如创建了采购单CG001,纸箱,1000 CG002,木板,500 ,供应商只发运了GC001的纸箱600,如果我想查询采购订单完成情况,应该怎么写?select * from purchases INNER JOIN
storehouse ON purchases.采购单 = dbo.storehouse.采购单
CG002因为还没进仓所以没有显示,感觉跟where purchases.采购单 = dbo.storehouse.采购单一个效果...我要把还没进仓的都显示出来,又不想创建时插入storehouse,因为送货单跟采购单是多对一,求教……
http://www.cnblogs.com/9421/archive/2010/01/20/1652242.html楼主看看上面博客,关于inner join,left(right) [outer] join,full join,cross join 的区别