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how to sum up in mysql

Posted on 2007-11-20
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Last Modified: 2008-02-23
I have a table in mysql called 'x' with columns a,b,c.

I want one sql statement that will sum up the following:

1) the entries in col 'a' where the date  <=  '2001-01-01'
2) the entries in col 'b' where the date  <=  '2001-01-01'
3)  the most recent entry in col 'c' where the date  <  '2001-01-01'

thanks!

Server info:
MySQL 5.0.45-community-nt via TCP/IP
MySQL Client Version 5.1.11
InnoDB tables
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Question by:jmokrauer
19 Comments
 
LVL 23

Expert Comment

by:Ashish Patel
Comment Utility
select Sum(Total) As TotalAll From
(select 'a' as col, sum(a) as Total from x where date  <=  '2001-01-01'
union
select 'b' as col, sum(b) as Total from x where date  <=  '2001-01-01'
union
select 'c' as col, sum(c) as Total from x where date  <  '2001-01-01' ) xyz
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Expert Comment

by:spprivate
Comment Utility
Select t1.val  +t2.val2
from (Select sum(a+b) as val  from x where date  <=  '2001-01-01' ) t1,
(Select sum(c) as val2  from x where date <  '2001-01-01' ) t2

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Author Comment

by:jmokrauer
Comment Utility
I dont see how the above solutions are doing the following:

3)  the most RECENT entry in col 'c' where the date  <  '2001-01-01'

Pls explain.  thanks
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Expert Comment

by:dansoto
Comment Utility
You are trying to pull 3 columns with a completely different amount of rows in each.  I'm not sure you can do that in one query.
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Expert Comment

by:dansoto
Comment Utility
BTW...I think your use of the word "sum" has thrown people off when you aren't really looking for a sum.  My understanding is that you want output that looks like:

ColA          ColB          ColC
1                1                 1
2                2                      
3                3      
4                  

Is that correct?
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Author Comment

by:jmokrauer
Comment Utility
dansoto,

No, I want the sum.  So the answer in the case below would be 21.  ColA & BolB will always have the same number of entries.

ColA          ColB          ColC
1                1                 1
2                2                      
3                3      
4                4

Thanks.
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Expert Comment

by:dansoto
Comment Utility
So what is missing from the solution by 'asvforce'?  His query should do the job..
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Author Comment

by:jmokrauer
Comment Utility
I am not sure but I don't think that the final part of his statement (which I put below) selects  the most RECENT entry to add to the sum of the other columns.  I think it sums all the entries before 2001-01-01.

"select 'c' as col, sum(c) as Total from x where date  <  '2001-01-01' )"

thanks for your perseverance & responsiveness



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Expert Comment

by:dansoto
Comment Utility
Ahh.. well probably confused the issue by including a date range in your question (  <  '2001-01-01).

So since you're pulling the "most recent".. the sum of that column will alway be "1"..right?
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Author Comment

by:jmokrauer
Comment Utility
No, it will be the value associated with the most recent date earlier than '2001-01-01'.

thanks.
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Expert Comment

by:dansoto
Comment Utility
Ok..I'm confused.  There can only be 1 most recent date ever... regardless of the timeframe, therefore that value will always be 1...
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Author Comment

by:jmokrauer
Comment Utility
The value in column 'c' associated with the most recent date might be a one, but it could be 425 or 1.8.  I don't know what value it is without looking it up.
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Expert Comment

by:dansoto
Comment Utility
Ok..so then colC is not a sum column.. but rather the unique iD of some record...right?
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Author Comment

by:jmokrauer
Comment Utility
yes
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Expert Comment

by:dansoto
Comment Utility
So we are back to what I stated a while ago... the term "sum" threw many people off.  You are not looking for a sum in column "C".  Only columns "a" and "b" would contains sum counts...
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Author Comment

by:jmokrauer
Comment Utility
sum(entries in colA where date<= '2001-01-01' )+sum(entries in colB where date<='2001-01-01' )+value of the most recent entry in colC where date< '2001-01-01'
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Expert Comment

by:dansoto
Comment Utility
Ok.. .try this then...


SET @a = (select sum(col_a) from x where date <=  '2001-01-01');

SET @b = (select sum(col_b) from x where date <=  '2001-01-01');

SET @c = (select col_c from x where date <= '2001-01-01' order by date desc limit 1);

SET @total = @a+@b+@c;

SELECT @total;

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Author Comment

by:jmokrauer
Comment Utility
It looks good but for my application, i need one sql statement. thanks.
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Accepted Solution

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dansoto earned 500 total points
Comment Utility
Ok.. try this:
Note that the last select statement has "some_other_column".   We need to select some other column to group by (other than colC) in order to have and even number of columns for the UNIONs to work.  Since it's only returning one value of use, it shouldn't matter which column.
select sum(Total) as complete_total from (

select colA as col, sum(colA) as Total from x where date <= '2001-01-01' group by colA

UNION

select colB as col, sum(colB) as Total from x where date <= '2001-01-01' group by colB

UNION

select some_other_column as col, max(colC) as Total from x where date <= '2001-01-01' group by some_other_column

) as tbl;

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