我们可以使用哪些 MySQL 函数来更改字符串的大小写?
mysqlmysqli database更新于 2025/5/16 14:36:17
我们可以使用 LCASE() 和 LOWER() 函数将字符串的大小写更改为小写，使用 UCASE() 和 UPPER() 函数将字符串的大小写更改为大写。
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用于表的列。例如，假设我们想更改输出中某一列的值的字符大小写，那么对表"Student"的以下查询可以演示这一点 −
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)
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