Selecting values from comma separated string

<div dir="ltr">Hi all,<br /><br />I want to write a function that takes as param a comma separated values string and
performa select matching these values.<br /><br />Here is the string '1,3,7,8'<br /><br />And I wan to perform a :
SELECT* FROM my_table WHERE id IN (1, 3, 7, 8);<br /><br />Does anyone have a clue ?<br /><br />Thanks<br /><br
/>Nacef<br/></div>