php - MySQL efficient: multiple tables or columns with nulls -

i developing mysql db user list, , trying determine efficient way design it.

my issue comes in there 3 types of users: "general", "normal", , "super". general , normal users differ in values of columns, schema store them identical. however, super users have @ least 4 columns of info needs stored.

in addition, each user needs unique user_id reference other parts of site.

so, can keep 3 users in same table, have lot of null values stored general , normal user rows.

or, can split users 2 tables: general/normal , super. rid of abundance of nulls, require lot more work keep track of user_ids , ensure unique, have handle in php instead of doing serial column in single table solution above.

which solution more efficient in terms of memory usage , performance?

or there another, better solution not seeing?

thanks!

why not build table; coloumns need super users? 2 tables 1 users , 1 super users's info