Question

I’m basically trying to group my traffic based on the traffic source

Lets say the table has the following columns

Enrollment_ID |      last_modified         | referrer
     1        |   2012-07-01 15:00:00      | http://www.facebook.com/l.php?xyz
     2        |   2012-07-01 16:00:00      | http://www.facebook.com/l.php?abc

Now the referrer is different – so even if I group it by referrer – it wont say 2
So this is the query I used

select count(*) as 'Enrollments',date_format(e.last_modified,'%d/%m/%y') as 'Date', if(LOCATE('facebook', referrer)>0,'facebook',referrer) as 'referrer'
from enrollment e
where e.last_modified >='2012-07-01 00:00:00'
group by date_format(e.last_modified,'%d/%m/%y'),3

This works fine. But obviously I’m going to have more than one referrer.
So I thought of using case statement

select count(*) as 'Enrollments',date_format(e.last_modified,'%d/%m/%y') as 'Date', 
case referrer
when LOCATE('facebook', referrer)>0 then 'facebook' 
when LOCATE('google', referrer)>0 then 'google' 
else referrer
end as 'referrer'
from enrollment e
where e.last_modified >='2012-07-01 00:00:00'
group by date_format(e.last_modified,'%d/%m/%y'),3

This does not work as expected.

For the first and second query – I have created a sql fiddle

First – http://sqlfiddle.com/#!2/70f6b/2

Second – http://sqlfiddle.com/#!2/ad890/3

I’ll appreciate if someone can take a quick glance at it

Thanks for your time

Answer 1

I never use MySQL, but I’m used to there being two types of CASE statements in other databases and you seem to be trying to mix them.

A

CASE <Field Name>
WHEN <value>...

B

CASE
WHEN <condition>...

So, just delete your first reference to referrer, and your query may work:

case
  when LOCATE('facebook', referrer)>0 then 'facebook' 
  when LOCATE('google', referrer)>0 then 'google' 
else referrer
end as 'referrer'

Another thing is that it might be cleaner to try to split referrer into several fields, where one of them was the internet address.