SQL中一列的不同逗號分隔值

Question

我在SQL查詢中返回以下結果：

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

我不想對語言有重復的值，所以如果我有兩種英語，我只需要顯示一種，那么結果應該是這樣的：

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

如何在SQL中做到這一點？

Answer 1

XQuery的

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

注釋后 ： 如果我添加了此行： insert into @temp values (4,'English, English, English') ，查詢返回給我“英語，英語”

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

Answer 2

現在，它可以很好地進行排序並獲得不同的值：

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')
insert into @temp values (4,'English, English, English')

select Id,
REPLACE( cast(cast('<d>'+ replace(languag, ', ','</d><d>')+'</d>'  as xml)
.query('for $a in distinct-values(/d) order by $a return $a') as varchar), ' ', ', ')AS [language]
from @temp

謝謝@tinka