3表连接查询

I'm curious to know what the best way to query this information with the active record query set for codeigniter.

I have 3 tables:

Table 1: "Titles"
         Fields: id, title_name

Table 2: "Roster"
         Fields: id, roster_name

Table 3: "Champions"
         Fields: id, title_id, champion_id, 
                 contender1_id, contender2_id, contender3_id

I'm tried doing this before but it just seems like it doesn't get done correctly because issues arise. Any ideas on how the query should be presented?

Any ideas from anyone?