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Count all Forward Slashes from MySQL and Count them

Posted on 2010-09-23
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Last Modified: 2012-06-21
Hi there,

I'm building an attendance register. Everything works fine with it. I now have to pull the records from the database and count them all to work out the overall attendance of each student.

All the rows could have any of these characters in them so i would need to fetch each row and count each character seperately:

/
C
H
I
J
L
M
O

Can any body help me? Let me know if ya need any more information

Thanks,
Craig
0
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Question by:projectstudios
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9 Comments
 
LVL 143

Expert Comment

by:Guy Hengel [angelIII / a3]
ID: 33744309
you mean:
select yourfield, count(*)
  from yourtable
 group by yourfield

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0
 
LVL 10

Expert Comment

by:Umar Topia
ID: 33744339
Solution provided by Angelll is correct
0
 
LVL 4

Expert Comment

by:max-hb
ID: 33744698
You want to calculate the numer of Cs, Hs, Os and so on?!
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LVL 8

Expert Comment

by:kingjely
ID: 33744767
Hi, I don't agree with the above,

If you need to count each occurance of the letters you mentioned, In a specific field,
<i would need to fetch each row and count each character seperately:

Then try this.

select
Case when Your_Field= '\\' then count(Your_Field) else '' end as 'Backslash',
Case when Your_Field = 'C' then count(Your_Field) else "" end as 'C',
Case when Your_Field = 'H' then count(Your_Field) else "" end as 'H',
Case when Your_Field = 'I' then count(Your_Field) else "" end as 'I',
Case when Your_Field = 'J' then count(Your_Field) else "" end as 'J',
Case when Your_Field = 'L' then count(Your_Field) else "" end as 'L',
Case when Your_Field = 'M' then count(Your_Field) else "" end as 'M',
Case when Your_Field = 'O' then count(Your_Field) else "" end as 'O'
from Your_table
Group by Your_Field;
0
 

Author Comment

by:projectstudios
ID: 33752132
Hi guys, Sorry about the long reply. Had to wait till i arrived back to work this morning.

I have tried your replies but i can't seem to get them to work.

Basically my table in my DB is attatched as an image.

As you can see each student will have a new row inserted every week under the that weeks week commencing date and then the row will be updated every day till Friday.

So i now need to pull all the specific rows to each student_id and calculate all the / marks aswell as any others so i can begin the maths to show the overall attendance percentage.

Does anybody know how i can achieve this?
Thanks,
Craig


table.jpg
0
 
LVL 143

Accepted Solution

by:
Guy Hengel [angelIII / a3] earned 500 total points
ID: 33752165
that would be:
select student_id
  , sum(
    case when mon_a = '/' then 1 else 0 end
  + case when mon_p = '/' then 1 else 0 end
  + case when tue_a = '/' then 1 else 0 end
  + case when tue_p = '/' then 1 else 0 end
  + case when wed_a = '/' then 1 else 0 end
  + case when wed_p = '/' then 1 else 0 end
  + case when thu_a = '/' then 1 else 0 end
  + case when thu_p = '/' then 1 else 0 end
  + case when fri_a = '/' then 1 else 0 end
  + case when fri_p = '/' then 1 else 0 end
   ) total_slashes
group by student_id

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Author Comment

by:projectstudios
ID: 33752200
Thanks for a quick reply angellll

That looks great but how do i echo the result from that?
0
 

Author Comment

by:projectstudios
ID: 33752212
nevermind, Done it :D
One last question for you if you don't mind.

Sometimes there might be a different character in there. Such as, C, H, I, J, L, M, O.

How do i amend that code to count those too?

Thanks
0
 
LVL 143

Expert Comment

by:Guy Hengel [angelIII / a3]
ID: 33752749
>How do i amend that code to count those too?
you can add the same expression, and replace the / by the relevant code.

or do you want to count all together? aka if it's not null, count it?
0

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