计算mysql中每个订单的订单项总数 [英] Count total number of order item of each order in mysql
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问题描述
我有一个如下表
|order_item_id|order_id|customer_id|
| 2 | 30 | 9 |
| 3 | 30 | 9 |
| 4 | 30 | 9 |
| 5 | 30 | 9 |
| 11 | 32 | 9 |
| 12 | 32 | 9 |
| 13 | 32 | 9 |
在这里,我想使用mysql计算每个order_id的order_item_id总数。
请帮助
here i would like to count total number of order_item_id for each order_id using mysql. please help
推荐答案
尝试一下:
select order_id, count(*) from t
group by order_id
来计数(*)
编辑:
是的,我知道,但实际上我想列出所有内容相关记录,而不仅仅是计数。 – user804457
yes this one i knew it, but actually i would like to list out all related records as well, not just count. – user804457
更改需求后,这似乎就是您要查找的内容:
After the requirements changed, then this seems to be what you're looking for:
select * from t t1
join (
select order_id, count(*) aCount from t
group by order_id
) t2
on t1.order_id = t2.order_id
结果:
+---------------+----------+-------------+--------+
| ORDER_ITEM_ID | ORDER_ID | CUSTOMER_ID | ACOUNT |
+---------------+----------+-------------+--------+
| 2 | 30 | 9 | 4 |
| 3 | 30 | 9 | 4 |
| 4 | 30 | 9 | 4 |
| 5 | 30 | 9 | 4 |
| 11 | 32 | 9 | 3 |
| 12 | 32 | 9 | 3 |
| 13 | 32 | 9 | 3 |
+---------------+----------+-------------+--------+
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