本文介绍了如何通过一个 SQL 查询获得多个计数?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我想知道如何编写这个查询.
I am wondering how to write this query.
我知道这个实际的语法是假的，但它会帮助你理解我想要什么.我需要这种格式，因为它是更大查询的一部分.
I know this actual syntax is bogus, but it will help you understand what I am wanting. I need it in this format, because it is part of a much bigger query.
SELECT distributor_id,
COUNT(*) AS TOTAL,
COUNT(*) WHERE level = 'exec',
COUNT(*) WHERE level = 'personal'
我需要在一个查询中返回所有这些.
I need this all returned in one query.
另外，它需要在一行中，所以下面的行不通:
Also, it need to be in one row, so the following won't work:
'SELECT distributor_id, COUNT(*)
GROUP BY distributor_id'
推荐答案
您可以将 CASE 语句与聚合函数一起使用.这与某些 RDBMS 中的 PIVOT 函数基本相同:
You can use a CASE statement with an aggregate function. This is basically the same thing as a PIVOT function in some RDBMS:
SELECT distributor_id,
count(*) AS total,
sum(case when level = 'exec' then 1 else 0 end) AS ExecCount,
sum(case when level = 'personal' then 1 else 0 end) AS PersonalCount
FROM yourtable
GROUP BY distributor_id
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