making specific query for big data

Hello all.. so Is it possible to do this: make query on mysql ask to select from blabla where bigdata= but tell to get only all data before --header end-- string into it so it will give in result only strings what are found before --header end-- becouse after this string goes very big data

any help with select query??

I have table one and table two I want to show all records from table one but also check if in table two is record that are in table one so if this is ture then bla=1 if false then bla=2 is it possible? query-"select tableone.user,tabletwo.user from tableone,tabletwo tableone.user=ta