mysql> select * from renshi; +-----------------+ | phone_sj | +-----------------+ | aaabbbccc | | dddeeeeeeffffff | +-----------------+ 2 rows in set (0.00 sec)select substring(phone_sj,4,(case when 2>1 then '2'-0 else '3'-0 end)) t from renshi;+------+ | t | +------+ | bb | | ee | +------+
to_number:ORACLE的函数 select substring(phone_sj,4,(case when 2>1 then 2 else 3 end)) t from renshi;
+-----------------+
| phone_sj |
+-----------------+
| aaabbbccc |
| dddeeeeeeffffff |
+-----------------+
2 rows in set (0.00 sec)select substring(phone_sj,4,(case when 2>1 then '2'-0 else '3'-0 end)) t
from renshi;+------+
| t |
+------+
| bb |
| ee |
+------+
select substring(phone_sj,4,(case when 2>1 then 2 else 3 end)) t
from renshi;