首先,这里的查询我就说说:预期结果 SELECT route_id, direction_id
FROM stop_times
LEFT JOIN trips USING (trip_id)
WHERE stop_id= 1002
GROUP BY CONCAT(route_id, direction_id)
例子: route_id | direction_id
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这是我的查询 SELECT PART_NUM,DESCRIPTION, CONCAT('$',(ON_HAND*PRICE)) AS ON_HAND_VALUE
FROM part WHERE CLASS ='AP'
但是当我试图查询它,我的回答将永远equall $ 0,它像(ON_HAND *价格)不工作 这些都是值:
Microwave Oven == 32*$165
GAS R
我的当前查询: - select
p.id as product_id,
p.product_name,
child.name as category_name,
parent.name as parent_category_name
from category child
left join products p on FIND_IN_SET(child.id,p.category_
我使用MySQL的双逗号冲突,运行一个查询的一些事情是这样的: SELECT GROUP_CONCAT(title,',') FROM `niuer_usergroups` where id IN (2,3,7,8)
并得到结果: Registered,,Author,,Administrator,,Super Users,
,但我想要的结果是这样的: Registered,Author,