This is personal study note Copyright and original reference: https://www.youtube.com/watch?v=QV12ZP50JSw&list=PLVsNizTWUw7HhYtI-4GGmlJ5yxNdwNI_Xs ================================================================================ select clause ================================================================================ Use clause ================================================================================ ================================================================================ ================================================================================ example data ================================================================================ PK: duplicate and NULL are not allowed for PK ================================================================================ In 1st record in buyTbl There is no address for that record ID KBS has full record in userTbl ================================================================================ Insert data into 2 tables