Loops and Function in Postgres

Hello, I require someone with strong experience with postgres and the plpsql language. I require to extract a list of distinct securities from a table over the past month. Using this list of securities I then require to create a LOOP that feeds each security into a function in postgres that I have already created. Upon executing the function I want to then output this security into a log table with a time stamp so can i keep track of what securities have been executed via this function. The results of this function will output a table with about 20 columns which need to be inserted into table inside the database. I have kept it quite brief and will provide more details to the winner. Should be a very easy task for the right person. Will like this done asap Just another point, the logic needs to be able to detect the securities in the log table also so that if I decide to schedule this function multiple times it wont be executing over the same list of securities as another function.