mysql - 从库存中获取可用设备的 SQL 语句

Question

我有一个表 equipment，其中包含 name、description、status 列

这是显示所有行时我的表格的样子:

id  name      description   status
1   shovel    shiny shovel     1
2   shovel    shiny shovel     1
3   shovel    shiny shovel     0
4   hammer    big hammer       1
5   hammer    big hammer       0

这是我现在的 SQL 语句:

SELECT equipment.name, equipment.description, COUNT(*) AS stock 
FROM equipment 
GROUP BY equipment.name

它显示以下内容:

name    description   stock
shovel  shiny shovel    3
hammer  big hammer      2

我想要的是显示另一列显示状态为 1 的设备数量

name    description   stock  available
shovel  shiny shovel    3       2
hammer  big hammer      2       1

Answer 1

您快完成了:您需要做的就是汇总状态字段，如下所示:

SELECT 
    equipment.name, 
    equipment.description, 
    COUNT(*) AS stock, 
    SUM(status) as available
FROM equipment 
GROUP BY 
    equipment.name,
    equipment.description