If you want to select these initial fields, then by combining them, you are replacing all that super fast functionality built into your database with interpreted PHP code to do the same job. You will probably end up with a lot of un-necessary string manipulation .
To get an idea of what should be in seperate columns and even tables, have a look at some of the relational database design papers and tutorials around on the internet.
Have a look at normalization theory and entity relationship diagrams.
They sound fancy but it all makes good sense once you get into it and can save a lot of time and effort further into a project if you need to change the database structure.
Good Luck
Paul
