Question

在mysql中使用count + where时，如何返回所有值？

MySQL的：

SELECT COUNT(*) as count , promocode FROM `dat_booking` WHERE promocode IN ("ABC","DEF","XYZ") GROUP BY promocode;

结果：

count  promocode
3      ABC
6      XYZ

但是我也想要如果它在表dat_booking中没有值它返回0

我想：

  count  promocode
   3      ABC
   0      DEF
   6      XYZ

感谢您阅读

Answer 1

SELECT 1 as req, promocode,count(*) FROM `dat_booking` WHERE promocode IN ("ABC","DEF","XYZ") GROUP BY promocode union select 2 as req, 'XYZ', 0 order by req

Answer 2

假设您有另一个表格，用于 promocodes 的静态值：

SELECT 
COUNT(*) as count , 
`dat_booking`.promocode 
FROM `dat_booking` LEFT JOIN `some_static_promocode_table`.promocode 
ON `some_static_promocode_table`.promocode = `dat_booking`.promocode 
WHERE `dat_booking`.promocode IN ("ABC","DEF","XYZ") GROUP BY 
`dat_booking`.promocode;

如何从mysql中的WHERE IN中获取所有值？

2 个答案: