significance of escape character in string in PHP

Question

I am having an string which was have few ' (single quote) and few " (double quotes) and was not able to insert into the mysql database. I have replaced them with \' and \" and everything is fine.
Though this are fine now but don't understand the working and I could have missed few corner cases also. Please suggest the working and also if there is some better way to achieve this.

Answer 1

You should be using either mysql_real_escape_string or mysqli_real_escape_string (preferably the
later) depending on how you're accessing the DB.

Answer 2

The mysql extension is officially not recommended for writing new
code, so anyone using it should be informed of this fact. I think it
should consist of more than "don't use that," but at the very least
that should cause the questioner to want to know why.

http://php.net/intro.mysql

This issue is problematic for exactly the reason Salil demonstrates
above: "it's working." Great that in this case it hasn't been left at
that, but most will see it work and think they've "got it right."