select t.train_id, t.train_no, t.err_code, t.sub_system, t.vehicle_order, t.err_status
from tbl_error t
where t.train_id='225' and t.train_no=13
group by t.train_id, t.train_no, t.err_code, t.sub_system, t.vehicle_order, t.err_status
order by t.tm_error descplsql提示“不是Group by表达式”。多谢
from tbl_error t
where t.train_id='225' and t.train_no=13
group by t.train_id, t.train_no, t.err_code, t.sub_system, t.vehicle_order, t.err_status
order by t.tm_error descplsql提示“不是Group by表达式”。多谢
你没有用到分组的任何函数。比如count(*),或者 avg,或者num等等。
如果你不用到的话,还不如不分组。直接select from order by呢!
select t.train_id, t.train_no, t.err_code, t.sub_system, t.vehicle_order, t.err_status
from tbl_error t
where t.train_id='225' and t.train_no=13
group by t.train_id, t.train_no, t.err_code, t.sub_system, t.vehicle_order, t.err_status
order by MIN(t.tm_error) desc
这里不能这样理解, group by有distinct的功能。
直接select from order by那样就可能有重复记录了
from tbl_error t
where t.train_id='225' and t.train_no=13
group by t.train_id, t.train_no, t.err_code, t.sub_system, t.vehicle_order, t.err_status
order by SUM(t.tm_error) desc