MySQL笔记之字符串函数的应用

mysql> SELECT RIGHT('nihao',3);
+------------------+
| RIGHT('nihao',3) |
+------------------+
| hao              |
+------------------+
 row in set (0.00 sec)

mysql> SELECT SUBSTRING_INDEX('HH,MM,SS',',',2);
+-----------------------------------+
| SUBSTRING_INDEX('HH,MM,SS',',',2) |
+-----------------------------------+
| HH,MM                             |
+-----------------------------------+
 row in set (0.00 sec)

mysql> SELECT SUBSTRING('helloworld',1,5);
+-----------------------------+
| SUBSTRING('helloworld',1,5) |
+-----------------------------+
| hello                       |
+-----------------------------+
 row in set (0.00 sec)

mysql> SELECT UPPER('hello');
+----------------+
| UPPER('hello') |
+----------------+
| HELLO          |
+----------------+
 row in set (0.00 sec)

mysql> SELECT LOWER('HELLO');
+----------------+
| LOWER('HELLO') |
+----------------+
| hello          |
+----------------+
 row in set (0.00 sec)

mysql> SELECT REVERSE('hello');
+------------------+
| REVERSE('hello') |
+------------------+
| olleh            |
+------------------+
 row in set (0.00 sec)

mysql> SELECT LTRIM('  hello     ');
+-----------------------+
| LTRIM('  hello     ') |
+-----------------------+
| hello                 |
+-----------------------+
 row in set (0.00 sec)

mysql> SELECT LENGTH('helo');
+----------------+
| LENGTH('helo') |
+----------------+
|              4 |
+----------------+
 row in set (0.00 sec)