Using If else conditional statement on where condition mysql

Using if / else on the mysql would be much easier to express with simple query. Her we go:

Assume you have the following table:

+--------------+--------------+------+-----+---------+----------------+
| Field        | Type         | Null | Key | Default | Extra          |
+--------------+--------------+------+-----+---------+----------------+
| file_id      | int(11)      | NO   | PRI | NULL    | auto_increment |
| file_path    | text         | NO   |     | NULL    |                |
| file_name    | varchar(120) | NO   | MUL | NULL    |                |
| file_size    | bigint(20)   | YES  |     | NULL    |                |
| file_content | text         | NO   | MUL | NULL    |                |
+--------------+--------------+------+-----+---------+----------------+

Then you want to collect records either by file_id or by file_size based on the file_size, if the file size above some value, check the name of the file to contain xls, otherwise, consider only files that have file id more than y

select * from file where if (file_size > x, file_name like '%.xls', file_id > y)

YUP!