simple table question

Hello,

Say I have table xyz with these fields:
id primary key auto increment
field1
field2
:::
fieldx
field_flag1 tinyint, #it has value either 1 or 0
field_flag2 tinyint, #it has value either 1 or 0
field_flag3 tinyint, #it has value either 1 or 0
field_flag4 tinyint, #it has value either 1 or 0
field_flag5 tinyint, #it has value either 1 or 0
field_flag6 tinyint, #it has value either 1 or 0
field_flag7 tinyint, #it has value either 1 or 0

When I do a query select, I'll check each flag field for 1 or 0 and process data. I'm thinking about instead of seven flags, I could use only one field 'field_flag', for example, and when insert table above, I could assign a value such as '0-1-0-0-1-1-1' to field_flag, and I could explode it later to an array (php) after retrieving it.

The first way takes more spaces to store all seven fields, and the second requires only one field but need to explode it, so which way is more efficient?

Thanks,
John