sql - SQL 中一列的不同逗号分隔值

Question

我有一个 SQL 查询返回以下结果:

Id language
1. English, French, spanish
2. English, English, spanish
3. French, French, English

我不想有重复的语言值，所以如果我有两种英语，我只需要显示一种，所以结果应该是这样的:

Id language
1. English, French, spanish
2. English, spanish
3. French, English

如何在 SQL 中做到这一点？

Answer 1

XQuery

declare @temp table (Id int,languag nvarchar(33))

insert into @temp values (1,'English, French, spanish')
insert into @temp values (2,'English, English, spanish')
insert into @temp values (3,'French, French, English')

select Id,
cast(cast('<d>'+replace(languag, ', ',',</d><d>')+'</d>'  as xml).query('distinct-values(/d)') as varchar) AS [language]
from @temp

评论后:如果我添加了这一行:插入@temp值(4，'English，English，English')查询将返回给我“英语，英语”

select Id,
REPLACE(cast(cast('<d>'+ replace(languag, ', ','</d><d>')+'</d>'  as xml)
.query('distinct-values(/d)') as varchar), ' ', ', ')AS [language]
from @temp;