Question

I have a problem creating some statistics for a conference where all visitors where scanned every time they entered and left the building.
I used mySQL and ‘stats’ table looks like this:

id(int) | accesscode(text) | in(datetime) | out(datetime)

And contains stats from 3 different days in the same table.
I want to get the statistics like this:

accesscode(text) first_entry(datetime) last_exit(datetime) no_of_exits(int) time_in day(int ex:1,2,3) 

This will result in three entries for each accesscode defined by day.

I tried several times but actually I have no clue how to do this.

Answer 1

 SELECT accesscode,
        MIN(`in`) as first_in,
        MAX(`out`) as last_out,
        count(*) as exit_count,
        sum(UNIX_TIMESTAMP(`out`) - UNIX_TIMESTAMP(`in`)) as seconds_attended
 FROM my_table
 GROUP BY accesscode