组合多个SQL查询

Question

我要进行查询，列出了高于平均水平的猫长卖猫？ 我有五个表：

动物，售，AnimalOrderItem，AnimalOrder，和SaleAnimal

  

动物表：AnimalID，名称，类别   （猫，狗，鱼）

     

SaleAnimal表：SaleID，AnimalID，   SalePrice

     

销售表：SaleID，日期，雇员，   客户id

     

AnimalOrderItem表：订单，   AnimalID，成本

     

AnimalOrder：订单，订购日期，   ReceivingDate，        供应商ID，ShippingCost，雇员

有是其他表我不认为他们对查询的效果。

我觉得以下...进行查询，以计算日为所有前卖：

[SaleDate]-[ReceiveDate] AS DaysToSell
Have the INNER JOIN built:
Sale INNER JOIN ((AnimalOrder INNER JOIN (Animal INNER JOIN AnimalOrderItem
ON Animal.AnimalID = AnimalOrderItem.AnimalID) ON AnimalOrder.
OrderID = AnimalOrderItem.OrderID) INNER JOIN SaleAnimal ON Animal.
AnimalID = SaleAnimal.AnimalID) ON Sale.SaleID = SaleAnimal.SaleID

创建基于上述查询另一个查询

SELECT AnimalID, Name, Category, DaysToSell
WHERE Category="Cat" AND DaysToSell>
(SELECT Avg(DaysToSell)
FROM the earlier query
WHERE Category="Cat"
ORDER BY DaysToSell DESC;

运行查询它，我得到了错误，说后

  

ORA-00921：SQL意外结束   命令

任何建议！请

Answer 1

查询可以与子查询相结合。例如，

select *
from (
    select * 
    from mytable
) subquery

应用这种模式，您的问题似乎相当简单。

Answer 2

我看不到，与相匹配的闭合支架上的SELECT AVG

Answer 3

好吧，我想出了这一点：

    SELECT AnimalID, Name, Category,
           [SaleDate]-[ReceiveDate] AS DaysToSell
    FROM   Sale INNER JOIN ((AnimalOrder INNER JOIN (Animal INNER JOIN AnimalOrderItem ON Animal.AnimalID = AnimalOrderItem.AnimalID) ON AnimalOrder.OrderID = AnimalOrderItem.OrderID)
           INNER JOIN SaleAnimal ON Animal.AnimalID = SaleAnimal.AnimalID) ON Sale.SaleID = SaleAnimal.SaleID
    WHERE  Category = "Cat"
    AND    ([SaleDate]-[ReceiveDate]) > (SELECT AVG([SaleDate]-[ReceiveDate])
                                         FROM   Sale INNER JOIN ((AnimalOrder INNER JOIN (Animal INNER JOIN AnimalOrderItem ON Animal.AnimalID = AnimalOrderItem.AnimalID) ON AnimalOrder.OrderID = AnimalOrderItem.OrderID)
                                         INNER JOIN SaleAnimal ON Animal.AnimalID =SaleAnimal.AnimalID) ON Sale.SaleID = SaleAnimal.SaleID
                                         WHERE Category = "Cat")
    ORDER BY ([SaleDate]-[ReceiveDate]) DESC;