当 CHAR_LENGTH() 或 CHARACTER_LENGTH() 字符串函数与 WHERE 子句一起使用时,其返回的输出将取决于 WHERE 子句中给出的条件。例如,假设我们有一个名为“Student”的表,并且我们只想获取那些字符数小于 6 的姓名,那么我们可以编写以下查询 -
mysql> Select * from Student;
+------+---------+---------+-----------+
| Id | Name | Address | Subject |
+------+---------+---------+-----------+
| 1 | Gaurav | Delhi | Computers |
| 2 | Aarav | Mumbai | History |
| 15 | Harshit | Delhi | Commerce |
| 20 | Gaurav | Jaipur | Computers |
+------+---------+---------+-----------+
4 rows in set (0.10 sec)
mysql> Select Name, CHAR_LENGTH(Name) from student WHERE CHAR_LENGTH(Name)