Extract Last Name only from Lastname,Firstname : <p>I just started working with Oracle recently so please bear with me.</p>

<p>I have a column of names as LASTNAME,FIRSTNAME and I need to extract JUST the last name. I know how to do this in excel, where I want to so search for the "," find the length of characters before the comma and return those characters. </p>

<p>I know to use SUBSTR as my LEFT() function, but I'm stuck from there.</p>
