请教SQLITE如何删除表内重复的记录

请教SQLITE如何删除表内重复的记录

$ sqlite3
SQLite version 3.7.13 2012-06-11 02:05:22
Enter ".help" for instructions
Enter SQL statements terminated with a ";"
sqlite> create table tb_test (id int, val char(32));
sqlite> insert into tb_test values (1, 'adb');
sqlite> insert into tb_test values (2, 'def');
sqlite> insert into tb_test values (2, 'ghi');
sqlite> insert into tb_test values (1, 'jkl');
sqlite> insert into tb_test values (3, 'mnu');
sqlite> select * from tb_test;
1|adb
2|def
2|ghi
1|jkl
3|mnu
sqlite> select * from tb_test a
...> where not exists (select 1
...> from tb_test b
...> where b.id = a.id
...> and a.rowid > b.rowid)
...> ;
1|adb
2|def
3|mnu
sqlite> .q
$