concat和concat_ws()区别及MySQL的几个实用字符串函数(3)

| id   | group_concat(name order by name desc) |
+------+---------------------------------------+
|    1 | 20,20,10                              |
|    2 | 20                                    |
|    3 | 500,200                               |
+------+---------------------------------------+
 
3 rows in set (0.00 sec)
 
4、repeat()函数，用来复制字符串,如下'ab'表示要复制的字符串，2表示复制的份数
 
mysql> select repeat('ab',2);
 
+----------------+
| repeat('ab',2) |
+----------------+
| abab           |
+----------------+
 
1 row in set (0.00 sec)
 
又如
mysql> select repeat('a',2);
 
+---------------+
| repeat('a',2) |
+---------------+
| aa            |
+---------------+
1 row in set (0.00 sec)