选择某些行的计数作为列

Question

我有一张表＆＃34;状态＆＃34;接受TINYINT的列。例如：

name   | status
-------+--------
john   | 0
joe    | 1
johann | 0
jan    | 1
jane   | 0

如何计算谁是状态1以及谁是状态0？

status1 | status0
--------+--------
2       | 3

Answer 1

只需使用条件聚合：

select sum(status = 1) as status1, sum(status = 0) as status0
from t;

在您的情况下，您也可以将其写为：

select sum(status) as status1, sum(1 - status) as status0
from t;

Answer 2

我会使用CASE语句来检查你的价值。

SELECT SUM(CASE WHEN [status] = 1 THEN 1 ELSE 0 END) AS Status1,
    SUM(CASE WHEN [status] = 0 THEN 1 ELSE 0 END) AS Status0
FROM tbl;