我可以在 Mysql 查询中使用 PHP function 吗？

Question

Following is my query and I would like to call PHP substr(); within Mysqlquery. Apparently, substr(ident.secondName, -2, 2) is working, but substr(ident.FirstName, 0, 2) is not working. Thank you in an advance!

mysqli_query($con, "select * from ident where ident.FirstName LIKE '%$first_name%' 
OR substr(ident.FirstName, 0, 2) = '$first_two' OR ident.FirstName IS NULL AND
(ident.SecondName LIKE '%$second_name%' OR substr(ident.SecondName, -2, 2) 
= $second_two' OR ident.SecondName IS NULL)");

Answer 1

No you cannot use a PHP function in a MySQL query, see the MySQL function reference for strings instead. MySQL also happens to have a SUBSTR function which is why the first case works.

Answer 2

不可以。您不能在mysql中使用PHP函数。

Answer 3

You're going to pass the query to you Mysql instance, it won't recognize the PHP code. So it's a no.

Answer 4

您可以为此使用子字符串功能

Answer 5

Use MySQL function SUBSTRING(): http://www.w3resource.com/mysql/string-functions/mysql-substring-function.php or use MySQL variables: How to declare a variable in MySQL?

If you want to do it with PHP you will have to get the data first to fill variables and apply functions.

Answer 6

Why not use function 'SUBSTRING' in MySql?

SUBSTRING('stackoverflow', 1, 5)
result : stack

SUBSTRING('stackoverflow', -13, 5)
result : stack

SUBSTRING('stackoverflow', 6)
result : overflow

SUBSTRING('stackoverflow', -8)
result : overflow