CASE Statement in codeigniter query

Question

I have following table of students

Attendance is of the month of November 2011

    date       absentperiod         name         

    2011-11-01      1               x        
    2011-11-01      5               x        
    2011-11-01      5               y        
    2011-11-01      1               z        

How to write sql query to find status? I am doing it in php.

I want to get output for employee x - absent , y - half day , z- half day

Students absent in period 1 and 5 should be absent Students absent in period 1 or 5 should be HALF DAY

Answer 1

Try this:

select date,
  first_period,
  fifth_period,
  name,
  case when first_period != fifth_period 
  then 'Half day' 
  else first_period end status
from my_table;