查找列中长度最长的字段

Question

如何在MySQL表中找到特定列长度最长的字段？

Answer 1

MySQL有很多可以使用的字符串函数:

SELECT LENGTH(col) as my_len FROM my_table ORDER BY my_len DESC LIMIT 1

更时髦的版本(它的工作原理):

SELECT MAX(LENGTH(col)) FROM my_table

Answer 2

你可以使用mysql命令LENGTH()

<?php 
$q = mysql_query("SELECT LENGTH(yourfield) AS fieldlength FROM yourtable ORDER BY fieldlength DESC LIMIT 1"); 
echo $longestfield = mysql_result($q,0); 
?>