[英]Oracle SQL order by expresion
I'm trying to sort something by an expression and for some reason it won't work unless I have that expression as a selection : 我正在尝试通过表达式对某事进行排序,由于某种原因,除非我将该表达式作为选择,否则它将无法工作:
select distinct p.stuff
from p.places
join otherPLACE
order by cos(sin(to_number(p.nr_matricol)));
But I keep getting this error 但我不断收到这个错误
ORA-01791: not a SELECTed expression
ORA-01791:不是SELECTED表达式
If I write it like this 如果我这样写
select distinct
p.stuff,
cos(sin(to_number(p.nr_matricol)))
from p.places
join otherPLACE
order by cos(sin(to_number(p.nr_matricol)));
it works but I don't want to have that column printed. 它可以工作,但我不想打印该列。
Is there a way I can make this work ? 有什么办法可以使我工作吗?
You can wrap into inline view 您可以包装到嵌入式视图中
SELECT a FROM
(select distinct p.stuff a, cos(sin(to_number(p.nr_matricol))) b
from p.places
join otherPLACE) T
ORDER BY b;
NOTE: I hope your code was pseudo-code. 注意:我希望您的代码是伪代码。 Because you-re having Cartesian join, unless you specifying columns
因为您要进行笛卡尔连接,除非您指定列
The problem is that the order by
takes place after the select distinct
. 问题在于,
order by
是在select distinct
之后发生的。 The only values available are those in the select
. 唯一可用的值是
select
。 A typical approach would be aggregation. 一种典型的方法是聚合。
Something like this: 像这样:
select p.stuff
from places p join
otherPLACE op
on . . .
group by p.stuff
order by cos(sin(to_number(max(p.nr_matricol))));
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