This is personal study note Copyright and original reference: https://www.youtube.com/watch?v=pSzsX_FaG7o&list=PLVsNizTWUw7HhYtI-4GGmlJ5yxNdwNI_X ================================================================================ <LEFT|RIGHT|FULL> LEFT: shows all records of LEFT table ================================================================================ Left table (userTble) shows all records even if those records are not in right table (buyTbl) ================================================================================ ================================================================================ Same result but right outer join ================================================================================ Shows the members who didn't buy product ================================================================================ ================================================================================ ================================================================================ Cross join (cartesian product) Cross join is meaningless except for the case where you create large data ================================================================================ ================================================================================ self join ================================================================================ ================================================================================