SQL LEN() 函數(shù)
LEN() 函數(shù)
LEN() 函數(shù)返回文本字段中值的長(zhǎng)度。
SQL LEN() 語(yǔ)法
SELECT LEN(column_name) FROM table_name;
MySQL 中函數(shù)為 LENGTH():
SELECT LENGTH(column_name) FROM table_name;
演示數(shù)據(jù)庫(kù)
在本教程中，我們將使用 php 樣本數(shù)據(jù)庫(kù)。
下面是選自 "Websites" 表的數(shù)據(jù)：
+----+--------------+---------------------------+-------+---------+
| id | name | url | alexa | country |
+----+--------------+---------------------------+-------+---------+
| 1 | Google | https://www.google.cm/ | 1 | USA |
| 2 | 淘寶 | https://www.taobao.com/ | 13 | CN |
| 3 | php中文網(wǎng) | http://miracleart.cn/ | 4689 | CN |
| 4 | 微博 | http://weibo.com/ | 20 | CN |
| 5 | Facebook | https://www.facebook.com/ | 3 | USA |
| 7 | stackoverflow | http://stackoverflow.com/ | 0 | IND |
+----+---------------+---------------------------+-------+---------+
| id | name | url | alexa | country |
+----+--------------+---------------------------+-------+---------+
| 1 | Google | https://www.google.cm/ | 1 | USA |
| 2 | 淘寶 | https://www.taobao.com/ | 13 | CN |
| 3 | php中文網(wǎng) | http://miracleart.cn/ | 4689 | CN |
| 4 | 微博 | http://weibo.com/ | 20 | CN |
| 5 | Facebook | https://www.facebook.com/ | 3 | USA |
| 7 | stackoverflow | http://stackoverflow.com/ | 0 | IND |
+----+---------------+---------------------------+-------+---------+
SQL LEN() 實(shí)例
下面的 SQL 語(yǔ)句從 "Websites" 表中選取 "name" 和 "url" 列中值的長(zhǎng)度：
實(shí)例
SELECT name, LENGTH(url) as LengthOfURL
FROM Websites;
FROM Websites;
執(zhí)行以上 SQL 輸出結(jié)果如下：
