MySQL nested, nested subquery not getting outter variable

Question

I have a spendings table and a dates table, that are joined by date_id and id...

What I'm trying to do, is get from 1 query all the info from spendings, plus the sum of all the spendings but with a limit and/or offset

This is the query right now

SELECT spendings.id, spendings.price, spendings.title, 
       dates.date, users.username, currencies.value,
       ( SELECT SUM(sum_table.price) 
         FROM (
             SELECT s.price
             FROM spendings s, dates d
             WHERE s.date_id = d.id 
               AND day(d.date) = 25
             LIMIT 2 OFFSET 0
         ) as sum_table
       ) AS sum_price
FROM spendings, dates, users, currencies
WHERE spendings.date_id = dates.id 
  AND day(dates.date) = 25 
  AND spendings.user_id = users.id 
  AND spendings.curr_id = currencies.id
LIMIT 2 OFFSET 0

Output

id  price   title   date       username value  sum_price
3   6.00    title1  2013-11-25 alex     €      21.00
4   15.00   title2  2013-11-25 alex     €      21.00

It works, but only if the date here day(d.date) = 25 is the same as the outer one here day(dates.date) = 25

If instead I put day(d.date) = day(dates.date) which seems the logic thing to do, I get #1054 - Unknown column 'dates.date' in 'where clause'

If anyone has an idea to make this simpler let me know :)

Answer 1

Try to join instead of using nested correlated subqueries:

SELECT spendings.id, spendings.price, spendings.title, 
      dates.date, users.username, currencies.value,
      y.sum_price
FROM spendings, dates, users, currencies
JOIN (
    SELECT day, SUM(sum_table.price) As sum_price
    FROM (
        SELECT day(d.date) As day,
               s.price
        FROM spendings s, dates d
        WHERE s.date_id = d.id 
          AND day(d.date) = 25
        LIMIT 2 OFFSET 0
    ) sum_table
    GROUP BY day
) y
ON y.day = day(dates.date)
WHERE spendings.date_id = dates.id 
  -- AND day(dates.date) = 25 <== commented since it's redundant now
  AND spendings.user_id = users.id 
  AND spendings.curr_id = currencies.id

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Some remarks:

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Using old join syntax with commas is not recommended: FROM table1,table2,table2 WHERE
The recommended way of expressing joins is "new" ANSI SQL join syntax:

FROM table1
[left|right|cross|[full] outer|natural] JOIN table2 {ON|USING} join_condition1
[left|right|cross|[full] outer|natural] JOIN table3 {ON|USING} join_condition2
....

Actually this "new syntax" is quite old now, since is has been published, as I remember, in 1992 - 22 years ago. In IT industry 22 years is like 22 ages.

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