alter table 테이블명 auto_increment = 1;
set @count = 0; //변수만들기
update 테이블명 set 변경할칼럼명 =@count:=@count+1;
mysql> alter table guide auto_increment = 1;
mysql> set @count = 0;
mysql> update guide set gu_num=@count:=@count+1;
mysql> select * from guide;
+--------+---------+------------+------------+
| gu_num | gu_year | gu_pr_num | gu_st_num |
+--------+---------+------------+------------+
| 1 | 2020 | 2010160001 | 2020160001 |
| 2 | 2020 | 2010160001 | 2020160002 |
| 3 | 2020 | 2011123001 | 2020123001 |
| 4 | 2020 | 2011123001 | 2020123002 |
| 5 | 2020 | 2006456001 | 2020456001 |
+--------+---------+------------+------------+