mysql字符串函数2

1.填充字符串的函数LPAD(s1,len,s2)和RPAD(s1,len,s2)

LPAD返回字符串s1，其左边由字符串s2填补到len字符长度。假如s1的长度大于len，则返回被缩短至len字符。

mysql> select lpad('hello',4,'??'),lpad('hell0',10,'??');
+----------------------+-----------------------+
| lpad('hello',4,'??') | lpad('hell0',10,'??') |
+----------------------+-----------------------+
| hell                 | ?????hell0            |
+----------------------+-----------------------+
1 row in set (0.00 sec)

RPAD返回字符串s1，其右边被字符串s2填补至len字符长度。假如字符串s1的长度大于len，则返回值被缩短到len字符长度

mysql> select rpad('hello',4,'??'),rpad('hell0',10,'??');
+----------------------+-----------------------+
| rpad('hello',4,'??') | rpad('hell0',10,'??') |
+----------------------+-----------------------+
| hell                 | hell0?????            |
+----------------------+-----------------------+
1 row in set (0.00 sec)