Postgresql Can'；无法解决此SQL查询

我很难处理SQL查询。我使用PostgreSQL

查询显示：显示至少完成了包含3个不同类别产品的订单的客户。结果将是两列，

CustomerID

，以及订单数量。我已经写了这段代码，但我认为它不正确

select SalesOrderHeader.CustomerID,
       count(SalesOrderHeader.SalesOrderID) AS amount_of_orders
from SalesOrderHeader 
inner join SalesOrderDetail on
       (SalesOrderHeader.SalesOrderID=SalesOrderDetail.SalesOrderID)
inner join Product on 
       (SalesOrderDetail.ProductID=Product.ProductID)

where SalesOrderDetail.SalesOrderDetailID in 
       (select DISTINCT count(ProductCategoryID)
        from Product
        group by ProductCategoryID
        having count(DISTINCT ProductCategoryID)>=3)

group by SalesOrderHeader.CustomerID;

以下是查询所需的数据库表：

永远不会给您一个结果，因为ID（

SalesOrderDetailID

）在逻辑上永远不会匹配

计数（
COUNT（ProductCategoryID）
）

这会让你得到我认为你想要的输出

SELECT soh.CustomerID, COUNT(soh.SalesOrderID) AS amount_of_orders
FROM SalesOrderHeader soh
INNER JOIN SalesOrderDetail sod ON soh.SalesOrderID = sod.SalesOrderID
INNER JOIN Product p ON sod.ProductID = p.ProductID
HAVING COUNT(DISTINCT p.ProductCategoryID) >= 3
GROUP BY soh.CustomerID

永远不会给您一个结果，因为ID（
SalesOrderDetailID
）在逻辑上永远不会匹配
计数（
COUNT（ProductCategoryID）
）

这会让你得到我认为你想要的输出

SELECT soh.CustomerID, COUNT(soh.SalesOrderID) AS amount_of_orders
FROM SalesOrderHeader soh
INNER JOIN SalesOrderDetail sod ON soh.SalesOrderID = sod.SalesOrderID
INNER JOIN Product p ON sod.ProductID = p.ProductID
HAVING COUNT(DISTINCT p.ProductCategoryID) >= 3
GROUP BY soh.CustomerID

试试这个：

select CustomerID,count(*) as amount_of_order from 
  SalesOrder join 
 (
   select SalesOrderID,count(distinct ProductCategoryID) CategoryCount 
     from SalesOrderDetail JOIN Product using (ProductId)
  group by 1
 ) CatCount using (SalesOrderId) 
 group by 1 
 having bool_or(CategoryCount>=3) -- At least on CategoryCount>=3

试试这个：

select CustomerID,count(*) as amount_of_order from 
  SalesOrder join 
 (
   select SalesOrderID,count(distinct ProductCategoryID) CategoryCount 
     from SalesOrderDetail JOIN Product using (ProductId)
  group by 1
 ) CatCount using (SalesOrderId) 
 group by 1 
 having bool_or(CategoryCount>=3) -- At least on CategoryCount>=3

你有错误吗？没有，但是根据给定的记录，输出不符合逻辑吗？没有，但是根据给定的记录，输出不符合逻辑。我执行它，我查看了数据（数据库中的记录太多）我认为输出不正确当数据中只有37个时，某些行的输出给出55个产品类别我执行它，我查看了数据（数据库中有太多记录），我认为输出不正确当数据中只有37个时，某些行的输出给出55个产品类别