SQL LCASE() 函数

LCASE() 函数把字段的值转换为小写。

 

1. LCASE() 语法

SELECT LCASE(column_name) FROM table_name;

用于 SQL Server 的语法

SELECT LOWER(column_name) FROM table_name;

样本数据库

在本教程中,我们将使用 CodeBaoku 样本数据库。

下面是选自 "Websites" 表的数据:

+----+--------------+---------------------------+-------+---------+
| id | name         | url                       | alexa | country |
+----+--------------+---------------------------+-------+---------+
| 1  | Google       | https://www.google.cm/    | 1     | USA     |
| 2  | 淘宝          | https://www.taobao.com/   | 13    | CN      |
| 3  | 编程宝库      | http://www.codebaoku.com/  | 4689  | CN      |
| 4  | 微博          | http://weibo.com/         | 20    | CN      |
| 5  | Facebook     | https://www.facebook.com/ | 3     | USA     |
|  6 | 百度         | https://www.baidu.com/    |     4 | CN      |
|  7 | stackoverflow | http://stackoverflow.com/ |     0 | IND     |
+----+---------------+---------------------------+-------+---------+

 

2. LCASE() 范例

下面的 SQL 语句从 "Websites" 表中选取 "name" 和 "country" 列,并把 "name" 列的值转换为小写:

SELECT LCASE(name) AS site_title, country FROM Websites;

执行结果:
+---------------+-------------+
| site_title    | country     |
+---------------+-------------+
| google        |    USA      |
| 淘宝           |    CN       |
| 编程宝库       |     CN      |
| 微博           |    CN       |
| facebook      |    USA      |
| 百度           |    CN       |
| stackoverflow |    IND      |
+---------------+-------------+

MID() 函数用于从文本字段中提取字符。SQL MID() 语法 SELECT MID(column_name,start[,length]) FROM table_name。