mysql - 从一行中选择两个不同的值

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我想要这张 table

预订表

+----+--------+
| ID | Status |
+----+--------+
| 1  | R      |
| 2  | R      |
| 3  | C      |
| 4  | C      |
+----+--------+

到这个总个数

+----------+-----------+
| Reserved | Cancelled |
+----------+-----------+
| 2        | 2         |
+----------+-----------+

到目前为止我得到了这个-

SELECT Status AS Reserves 
FROM Booking WHERE Status = 'R' OR Status = 'C'

输出-

+----------+
| reserves |
+----------+
| R        |
| C        |
| R        |
| C        |
+----------+

最佳答案

将 WHERE 子句中的逻辑放入 CASE 表达式中，并对整个表求和:

SELECT
    SUM(CASE WHEN Status = 'R' THEN 1 END) AS Reserved,
    SUM(CASE WHEN Status = 'S' THEN 1 END) AS Cancelled
FROM Booking

关于mysql - 从一行中选择两个不同的值，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/43772029/