如何在SQL中删除重复的行 [英] How to remove duplicate rows in SQL

问题描述

我要删除以下数据中的重复行.

I want to remove duplicate rows in the following data.

数据:

a       a
a       b
a       c
a       d
a       e
b       a
b       b
b       c
b       d
b       e
c       a
c       b
c       c
c       d
c       e
d       a
d       b
d       c
d       d
d       e
e       a
e       b
e       c
e       d
e       e

输出应与column1和column2不同. 且不应为以下数据.

The output should be column1 and column2 different. and it should not be the following data.

a       b
a       c
a       d
a       e
b       a
b       c
b       d
b       e
c       a
c       b
c       d
c       e
d       a
d       b
d       c
d       e
e       a
e       b
e       c
e       d

因为第1列中的a和第2列中的b与第1列中的b和第2列中的a相同，否则我只是说1 + 2与2 + 1相同.

because a in column 1 and b in column2 is same as b in column1 and a in column2 or else simply i mean to say 1+2 is same as 2+1.

因此，输出应为

a,b
a,c
a,d
a,e
b,c
b,d
b,e
c,d
c,e
d,e

推荐答案

select distinct least(column_1, column_2), greatest(column_1, column_2)
from the_table
where column_1 <> column_2;

这篇关于如何在SQL中删除重复的行的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！