MYSQL在两列中选择DISTINCT值 [英] MYSQL select DISTINCT values in two columns
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问题描述
我想在数据库中选择不同的值.让我为您介绍一个简单的例子.
I want to select distinct values in a database. Let me run you through a quick example.
表格:
foo bar
--- ---
a c
c f
d a
c a
f c
a c
d a
a c
c a
f c
对,假设我的SQL是SELECT DISTINCT foo, bar from table
.这些是我的结果:
Right, let's say my SQL is SELECT DISTINCT foo, bar from table
. These are my results:
foo bar
--- ---
a c
c f
d a
c a
f c
但是,问题是a c
/c a
重复存在,只是它们的顺序不同.我不想选择这些,我希望这两列中都有不同的值,请帮忙!
However the problem is is that there are repetitions of a c
/ c a
just that they are in a different order. I don't want to select these, I want distinct values from both columns, please help!
推荐答案
非常邪恶&邪恶:
very very wicked & evil:
select distinct
least(foo, bar) as value1
, greatest(foo, bar) as value2
from table
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