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I have a table that looks something like this:

Name Year Value A 2000 5 A 2001 3 A 2002 7 A 2003 1 B 2000 6 B 2001 1 B 2002 8 B 2003 2

The user can query based on a range of years, and it will return the sum of Value grouped by Name, as such (assume queried years are 2000 - 2001):

Name SUM(Value) A 8 B 7

Now, I wanted to insert a calculated field that outputs the ratio of the sum of the values of each name for ALL years to the sum of all values. Basically the percentage of all values attributed to A and B, respectively, like:

Name SUM(Value) % Of Total A 8 0.484 (16 / 33) B 7 0.516 (17 / 33)

Note that even though the user queried only 2000-2001, I want the calculation to use the sum across all years. I've been searching and experimenting for hours and I cannot figure out how. I only know how to sum across the queried years like so:

SELECT `Name`, SUM(`Value`)/(SELECT SUM(`Value`) FROM `table1`) AS "% of Total" FROM `table1` WHERE `Year` BETWEEN 2000 AND 2001 GROUP BY `Name`;
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3 Answers 3

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123

You can calculate the total (and from that the desired percentage) by using a subquery in the FROM clause:

SELECT Name, SUM(Value) AS "SUM(VALUE)", SUM(Value) / totals.total AS "% of Total" FROM table1, ( SELECT Name, SUM(Value) AS total FROM table1 GROUP BY Name ) AS totals WHERE table1.Name = totals.Name AND Year BETWEEN 2000 AND 2001 GROUP BY Name;

Note that the subquery does not have the WHERE clause filtering the years.

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1 Comment

Easiest to understand and worked like a charm. Thank you so much!
28

If you want to SELECT based on the value of another SELECT, then you probably want a "subselect":

http://beginner-sql-tutorial.com/sql-subquery.htm

For example, (from the link above):

  1. You want the first and last names from table "student_details" ...

  2. But you only want this information for those students in "science" class:

     SELECT id, first_name FROM student_details WHERE first_name IN (SELECT first_name FROM student_details WHERE subject= 'Science');
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5 Comments

The sample is not helpful at all, as long as subquery makes no sense there
I have that much down, but I can't figure out the syntax. I'm trying to include a value from an inner table that relies on the value from the outer table.
Book recommendation: amazon.com/SQL-Queries-Mere-Mortals-Manipulation/dp/0321444434 Personally, I've found it very helpful. I honestly think you might like it, too. IMHO...
SELECT id, first_name FROM student_details WHERE subject = 'Science' isnt it exactly same?
Quick note: it is very normal for editors to remove "hope this helps" and other conversational asides. There is a broad consensus to use technical writing here.
4 
SELECT x.name, x.summary, (x.summary / COUNT(*)) as percents_of_total FROM tbl t INNER JOIN (SELECT name, SUM(value) as summary FROM tbl WHERE year BETWEEN 2000 AND 2001 GROUP BY name) x ON x.name = t.name GROUP BY x.name, x.summary
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