Mandatory skills to land a php programmer job

I wanted to ask the mandatory or basic knowledge required for php and mysql to land a job.although i have knowledge of php but sometimes i get stuck.e.g, there was a scenario of a job that they handled me for was showing prices of respective currency when it is clicked upon.although i made a table for currency and do the stuck.but i couldn’t figure out on how to get primary table and make a loop for displaying each item in the currency which was selected. rather it was one item repeating itself.
I want some hardcore basic knowledge to get me a job and can do things.of course when projects come, u learn.but wht mandatory skills do i learn for basic.