php with if( $ this- > count( ) ) ). Implement that function or change calling it the function should be from different class. ( $ this- > _ db- > count ( ). When i execute my PHP code below i get a Fatal error and i' m not sure how to resolve it. Thank you for your help The Error PHP Fatal error: Uncaught Error: Call to undefined function mysql_ qu. After incrementing, I wanted to update a custom field. So, I tried to use some acf field functions. But, I get an error, Uncaught Error: Call to undefined function the_ field( ). Here is the entire code.