此代码有效:
select Date1, Date2
from
(SELECT Date1 FROM Table1 GROUP BY Date1) t1
left join
(SELECT Date2 FROM Table2 GROUP BY Date2) t2
on
t1.Date1 = t2.Date2
但是我需要使用它来提取Month(...),所以当我更改这样的代码时,我得到了一个错误:
“字段列表”中的未知列“ Date1”
select Date1, Date2
from
(SELECT Month(Date1) FROM Table1 GROUP BY Date1) t1
left join
(SELECT Month(Date2) FROM Table2 GROUP BY Date2) t2
on
t1.Date1 = t2.Date2
实际上,代码更大,并且只有这部分代码不允许我继续进行。
最佳答案
内部选择查询中缺少month
的别名
select Date1, Date2
from
(SELECT Month(Date1) as date1 --Alias missing Here
FROM Table1
GROUP BY Date1) t1
left join
(SELECT Month(Date2) as date2 --Alias missing here
FROM Table2
GROUP BY Date2) t2
on
t1.Date1 = t2.Date2
关于mysql - sql在选择语句中使用Month(date)的左连接错误,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/31773852/