Using PHP to pull out records from table in MySQL database

Source: stackoverflow.com --- Sunday, April 30, 2017
I am asked to pick up the team, teamid, pennants, and worldseries columns from the champs and teamstats tables. and print the number of Baseball teams in the champs table. I have 2 files as following. I keep getting warnings saying Warning: mysqli_num_rows() expects parameter 1 to be mysqli_result, null given in /Users/ //// SECOND FILE