wpdb_prepare with multiple or condition

I think your first partial code be this partial code:

$wpdb->prepare( "SELECT * ... from ... WHERE ( post_title LIKE '%%%s%%' or post_content LIKE '%%%s%%' )..., $string, $string );

You have to have to pass the same number of arguments into the query as you specify (with %s) in it.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)