我们可以使用哪些 MySQL 函数来更改字符串的字符大小写？

我们可以使用 LCASE() 和 LOWER() 函数将字符串的字符大小写更改为小写，使用 UCASE() 和 UPPER() 函数将字符串的字符大小写更改为大写。

示例

mysql> Select LCASE('NEW DELHI');

+--------------------+
| LCASE('NEW DELHI') |
+--------------------+
| new delhi          |
+--------------------+

1 row in set (0.00 sec)

mysql> Select LOWER('NEW DELHI');

+--------------------+
| LOWER('NEW DELHI') |
+--------------------+
| new delhi          |
+--------------------+

1 row in set (0.00 sec)

mysql> Select UCASE('new delhi');

+--------------------+
| UCASE('new delhi') |
+--------------------+
| NEW DELHI          |
+--------------------+

1 row in set (0.00 sec)

mysql> Select UPPER('new delhi');

+--------------------+
| UPPER('new delhi') |
+--------------------+
| NEW DELHI          |
+--------------------+

1 row in set (0.00 sec)

我们还可以将这些函数与表的列一起使用。例如，假设我们想要更改输出中列中值的字符大小写，然后对表“Student”进行以下查询可以演示它 -

mysql> Select Name, UCASE(Name) from student;

+---------+-------------+
| Name    | UCASE(Name) |
+---------+-------------+
| Gaurav  | GAURAV      |
| Aarav   | AARAV       |
| Harshit | HARSHIT     |
| Gaurav  | GAURAV      |
| Yashraj | YASHRAJ     |
+---------+-------------+

5 rows in set (0.00 sec)

mysql> Select Name, LCASE(Name) from student;

+---------+-------------+
| Name    | LCASE(Name) |
+---------+-------------+
| Gaurav  | gaurav      |
| Aarav   | aarav       |
| Harshit | harshit     |
| Gaurav  | gaurav      |
| Yashraj | yashraj     |
+---------+-------------+

5 rows in set (0.00 sec)

mysql> Select Name, UPPER(Name) from student;

+---------+-------------+
| Name    | UPPER(Name) |
+---------+-------------+
| Gaurav  | GAURAV      |
| Aarav   | AARAV       |
| Harshit | HARSHIT     |
| Gaurav  | GAURAV      |
| Yashraj | YASHRAJ     |
+---------+-------------+

5 rows in set (0.00 sec)

mysql> Select Name, LOWER(Name) from student;

+---------+-------------+
| Name    | LOWER(Name) |
+---------+-------------+
| Gaurav  | gaurav      |
| Aarav   | aarav       |
| Harshit | harshit     |
| Gaurav  | gaurav      |
| Yashraj | yashraj     |
+---------+-------------+

5 rows in set (0.00 sec)