Almost any business database can be used for sports industry information. This page lists databases that specifically cover sport, but I encourage you to use other industry databases, marketing databases, and article databases for your research.
Check out the Industry & Market Research Basics Tutorial to learn how to use the general industry and market research databases. The 60-minute tutorial will give you a foundation in using library databases to conduct industry and consumer market research, which will be useful for sports industry and sports marketing projects.
Business Source Complete can be a great resource when looking for articles about sport teams, marketing, properties, fans, and more. I recommend you use both SPORTDiscus and Business Source Complete to make sure you have covered all your bases. (pun intended).