sql中去除重复的项

用slq语句实现除去字段T中重复的项：
ID     T
1     1-2
2     2-3
3     3-4
4     1-2
5     2-3

所要结果：
ID     T
1     1-2
2     2-3
3     3-4
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找到正解：
select a.id,a.t from Table_1 as a inner join(select id=min(id) from Table_1 group by t) as b on a.id=b.id

select * from Table_1 where ID in (select id=min(id) from Table_1 group by t)

两个sql都可以，关键是select id=min(id) from Table_1 group by t