MySQL UNION - 每个派生表必须有自己的别名
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MySQL UNION - Every derived table must have its own alias
提问by user3270967
I am looking for a solution:
我正在寻找解决方案：
SELECT SUM(`quant`), MONTH(`date`) AS month, `id` from (
(SELECT `date`, `id`, count(`hit`) AS `quant ` FROM `stat_2014_07` WHERE `k_id` = '123')
UNION ALL
(SELECT `date`, `id`, count(`hit`) AS `quant ` FROM `stat_2014_08` WHERE `k_id ` = '123')
) group by id, month
MySQL: Every derived table must have its own alias
MySQL：每个派生表都必须有自己的别名
回答by Mureinik
You need to give aliases to your queries:
您需要为您的查询提供别名：
SELECT SUM(`quant`), MONTH(`date`) AS month, `id`
FROM ((SELECT `date`, `id`, count(`hit`) AS `quant`
FROM `stat_2014_07`
WHERE `k_id` = '123') t1
UNION ALL
(SELECT `date`, `id`, count(`hit`) AS `quant`
FROM `stat_2014_08`
WHERE `k_id ` = '123') t2
) t_union
GROUP BY id, month
回答by a_horse_with_no_name
Exactly what the error message says. In your (simplified) query:
正是错误消息所说的。在您的（简化）查询中：
SELECT SUM(`quant`), MONTH(`date`) AS month, `id`
from (
... inner select
)
group by id, month;
You didn't specify an alias for the derived table. So it should be:
您没有为派生表指定别名。所以应该是：
SELECT SUM(`quant`), MONTH(`date`) AS month, `id`
from (
... inner select
) as t -- this is the change
group by id, month;
Btw: the parentheses around the select parts of a union are totally useless. I suggest removing them for clarity:
顺便说一句：联合选择部分周围的括号完全没用。为了清楚起见，我建议删除它们：
SELECT SUM(`quant`), MONTH(`date`) AS month, `id`
from (
SELECT `date`, `id`, count(`hit`) AS `quant ` FROM `stat_2014_07` WHERE `k_id` = '123'
UNION ALL
SELECT `date`, `id`, count(`hit`) AS `quant ` FROM `stat_2014_08` WHERE `k_id ` = '123'
) as t -- this is the change
group by id, month;
