SQL-计算一个属性，按另一个属性分组

我有一张桌子

staff

staff
pt | ward
P  | 1
P  | 1
T  | 1
P  | 2
T  | 2

我想制作一个表格，计算每个病房有多少个p's和T's，如下所示：

staff
ward | P | T
1    | 2 | 1
2    | 1 | 1

我试过这个

WITH cte(ward, P, T) AS(
SELECT ward,
(SELECT COUNT(PT) FROM staff WHERE PT = 'P' ),
(SELECT COUNT(PT) FROM staff WHERE PT = 'T' ) FROM staff GROUP BY ward)
SELECT * FROM cte

但是我得到了这张桌子

staff
ward | P | T
1    | 3 | 2
2    | 2 | 2

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任何帮助都将不胜感激

使用条件聚合：

select ward, sum( (pt = 'P')::int ) as p, sum ( (pt = 'T')::int ) as t
from t
group by ward;

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案例陈述将在这里起作用：

SELECT
    ward,
    SUM(CASE WHEN pt = P THEN 1 ELSE 0 END) AS P,
    SUM(CASE WHEN pt = T THEN 1 ELSE 0 END) AS T
FROM
    table
GROUP BY
    ward