如何仅检查来自mysql单元的前两个字母？

Question

I want to check a row in an mysql table for the username in php, if the username starts with ab to write an text.

the username is in a cell and looks like this: ab_12345453.

Thanks, Sebastian

EDIT:

thank you all for your reply. but i need something else. i need this for joomla, i don't need to make an query, i just use: $user->username and i get the logged in username.

so i have the logged in username in a variable. how can i check that the username starts with ab_ ?

thank you again and sorry for the confusion :(

Answer 1

SELECT * FROM bar B where B.username LIKE 'ab%';

请参阅此处的手册。

Answer 2

使用带有单个％通配符的LIKE命令说出任意字符

SELECT * FROM table WHERE col LIKE 'ab%';

Answer 3

I vote for Artefacto's solution, and add to it a recommendation:

alter table bar add key(username(2));

In case you don't have an index for the column.

Answer 4

use can use also substring

http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_substring