如何合并 SQL 查询的两个结果

Question

我正在尝试将两个 sql 查询的结果合并为一个

查询 1：

SELECT COUNT(class) as show, year
FROM lee
where class = 'Show'
GROUP BY year

结果

show         year
185          2016
296          2020
655          2019

查询 2

SELECT COUNT(class) as movie, year
FROM lee
where class = 'movie'
GROUP BY year

结果

   movie           year
    556          2016
    987          2020
    690          2019

我如何实现这样的目标：

        movie          show           year
        556            185           2016
        987            296           2020
        690            655           2019

Answer 1

您可以使用 case when 语句选择计数类。

SELECT count(CASE WHEN class = 'movie' THEN 1 END) as movie,
       count(CASE WHEN class = 'show' THEN 1 END) as show,
       year
FROM lee
GROUP BY year;

Answer 2

使用条件聚合：

SELECT SUM(CASE WHEN class = 'show' THEN 1 ELSE 0 END) as show,
       SUM(CASE WHEN class = 'movie' THEN 1 ELSE 0 END) as movie,
       year
FROM lee
GROUP BY year;

Answer 3

我的解决方案不是最漂亮的，但它是给另一个选择

SELECT m.movie, s.show, m.YEAR FROM
(SELECT COUNT(1) AS movie, YEAR FROM LEE WHERE CLASS = 'movie' GROUP BY YEAR) m
JOIN (SELECT COUNT(1) AS show, YEAR FROM LEE WHERE CLASS = 'show' GROUP BY YEAR) s 
ON (s.YEAR = m.YEAR);