SQL LEN()
SQL LEN() 函數
LEN() 函數
LEN() 函數傳回文字欄位中值的長度。
SQL LEN() 語法
SELECT LEN(column_name) FROM table_name;
MySQL 中函數為LENGTH():
SELECT LENGTH(column_name) FROM table_name;
示範資料庫
在本教學中，我們將使用php 樣本資料庫。
下面是選自"Websites" 表的資料：
+----+--------------+--- ------------------------+-------+---------+
| id | name | url | alexa | country |
+----+----------+------------------------------------ --------+-------+---------+
| 1 | Google | https://www.google.cm/ | 1 | USA | 1 |
| 2 | 淘寶 | https://www.taobao.com/ | 13 | CN cn/ | 4689 | CN |
| 4 | 微博 | http://weibo.com/ | 201 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 | 1 |
| 2 | 淘寶 | https://www.taobao.com/ | 13 | CN cn/ | 4689 | CN |
| 4 | 微博 | http://weibo.com/ | 201 https://www.facebook.com/ | 3 | USA |
| 7 | stackoverflow | http://stackoverflow.com/ | 0 | IND |
+----+---------------+----------- ------------------+-------+---------+
下面的SQL 語句從"Websites" 表中選取"name" 和"url" 欄位中值的長度：
實例SELECT name , LENGTH(url) as LengthOfURL
FROM Websites;#執行上述SQL 輸出結果如下：
