*Simple/FastProject* Figure out why JOINING 4 tables doesn't show results in mysql

I have 4 tables: Companies Sectors CompaniesData SectorsData Companies and Sectors tables will updated about once a month while CompaniesData and SectorsData will be updated daily so in my understanding I can't have only 2 tables since it would be a lot of unnecesary data every day. For instance: SectorID, CompanyID, CompanyName, CompanyLinkProfile that belongs to the first 2 tables it always will be the same but other kind of information like TodayPrice, TodayTrend will be added daily. Having only 2 tables will result in some kind of (see atached image) CompanyID | SectorID | CompanyLinkProfile | TodayPrice | TodayTrend 45 | 14 | http:// link to any | $30 | Up 45 | 14 | http:// link to any | $35 | Down 45 | 14 | http:// link to any | $50 | Up *Note only the 2 last columns are changing. PROBLEM: Using 4 tables and with this query is not giving me any results despite the fact that there is data in every table: SELECT [login to view URL] , [login to view URL] , [login to view URL] , [login to view URL] FROM Companies AS c JOIN Sectors AS s ON [login to view URL] = [login to view URL] JOIN CompanyPriceRS AS cprs ON [login to view URL] = [login to view URL] JOIN SubSectorsBPIsData AS ssbpi ON [login to view URL] = [login to view URL] If I remove the last JOIN line then i get proper result but that's not what i want. I need the 4 tables involved. I have added indexes to almost any column so i think that's not the problem. YOUR TASK: Figure out why this query is not working, fixing it and tell me what you did. Or figure out another way of handle this issue and explain it to me. I'll only reply proposals from people who actually read this project and contact me with keyword: lucino Easy, fast and simple money :) Thanks for your time