Question

给出以下样本表模式

客户表

CustID
1
2
3

发票表

CustID InvoiceID

1       10
1       20
1       30
2       10
2       20
3       10
3       30

目标是选择InvoiceID值为10和20（非OR）的所有客户。因此，在此示例中，将返回客户w / CustID = 1和2。

您将如何构造SELECT语句？

Answer 1

使用：

  SELECT c.custid
    FROM CUSTOMER c
    JOIN INVOICE i ON i.custid = c.custid
   WHERE i.invoiceid IN (10, 20)
GROUP BY c.custid
  HAVING COUNT(DISTINCT i.invoiceid) = 2

关键是i.invoiceid的计数需要等于IN子句中的参数数量。

如果对custid和invoiceid的组合没有唯一约束，则使用COUNT(DISTINCT i.invoiceid) - 如果没有重复的可能性，则可以省略查询中的DISTINCT：

  SELECT c.custid
    FROM CUSTOMER c
    JOIN INVOICE i ON i.custid = c.custid
   WHERE i.invoiceid IN (10, 20)
GROUP BY c.custid
  HAVING COUNT(i.invoiceid) = 2

Answer 2

除非可能在Invoice表中有多个CustID / InvoiceId，否则Group By答案将起作用。然后你可能得到一些意想不到的结果我更喜欢下面的答案，因为它更能反映出你所描述的逻辑。

Select CustID
From Customer
Where
  Exists (Select 1 from Invoice Where CustID=Customer.CustID and InvoiceID=10)
and
  Exists (Select 1 from Invoice Where CustID=Customer.CustID and InvoiceID=20)

Answer 3

select CustID
    from InvoiceTable
    where InvoiceID in (10,20)
    group by CustID
    having COUNT(distinct InvoiceID) = 2

如何选择多个连接表值满足选择条件的行？

3 个答案: