How to parse without changing the characters case (lower and upper) in wordpress the_content?

Kitefr, (this isn’t really a WordPress question, but a php one) but you could usepreg_replace_callback, in which you define your own function to handle the the replacement.

For instance,

    $text = "The quick brown fox jumped over the Quick dog.";
    $text = preg_replace_callback( "/quick/si", 'my_replace' , $text );
    function my_replace($matches){
         return '<strong>'.$matches[0].'</strong>';
    }

This replaces all instances of ‘quick’ (in any case) and wraps them with strong tags, leaving the case of the letters unchanged. You could do something similar with link tags

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