mysql - 在 SQL 查询中创建自定义列

Question

我有一个这样的表:

ITEM    PICTURE    CATEGORY    STOCK
 1      Mickey     Shirt        3
 2      Mickey     Jacket       2
 3      Donald     Jacket       0
 4      Donald     Shirt        6
 5      Donald     Hoodie       1
 6      Mickey     Hoodie       3
 7      Goofy      Shirt        1
 8      Goofy      Hoodie       2
 9      Goofy      Jacket       3

ITEM列自动递增

我需要这样的输出:

PICTURE    HOODIE    JACKET    SHIRT
Donald       1         0         6
Goofy        2         3         1
Mickey       3         2         3

知道如何产生该输出吗？谢谢

Answer 1

您可以使用CASE表达式。

查询

select PICTURE,
sum(case CATEGORY when 'Hoodie' then STOCK else 0 end) as `HOODIE`,
sum(case CATEGORY when 'Jacket' then STOCK else 0 end) as `JACKET`,
sum(case CATEGORY when 'Shirt' then STOCK else 0 end) as `SHIRT`
from your_table_name
group by PICTURE;