如何根据列中值的计数比较来提取记录

Question

请原谅标题，但我不知道该写些什么。所以这就是我所拥有的 -

CUSTOMER（KEY, IDENT, DEBIT_CREDIT）

1,1000,'D'
2,1000,'C'
3,1001,'D'
4,1000,'D'
5,1000,'D'
.
.
.

我想写一个SQL Server查询来提取相同的IDENT，其中'D'的计数大于'C'的计数

Answer 1

首先：

SELECT IDENT
FROM CUSTOMER
GROUP BY IDENT
HAVING  SUM(CASE WHEN DEBIT_CREDIT = 'D' THEN 1 ELSE 0 END) >
        SUM(CASE WHEN DEBIT_CREDIT = 'C' THEN 1 ELSE 0 END)

第二

SELECT IDENT
FROM CUSTOMER
GROUP BY IDENT
HAVING  SUM(CASE WHEN DEBIT_CREDIT = 'D' THEN 1 ELSE 0 END) =
        SUM(CASE WHEN DEBIT_CREDIT = 'C' THEN 1 ELSE 0 END)