SQL Sum() with correlated subquery

Question

I have two tables: fund and items. Items has a field called fundID that is related to the ID of the fund table. Items also has a price field.

Here's a simplified example of the two tables:

FUND
ID    fundName
1     maintenance
2     books
3     development
4     media


ITEMS
ID    price    fundID
1     $10        2
2     $20        4
3     $5         4
4     $8         1
5     $10        3
6     $12        4

I want to create a query that will give me the name of each fund and the sum of all prices for items that are connected to that fund through the fundID field. I have tried several methods such as having a correlated subquery within the SUM() and also within the WHERE, and I am getting errors.

If someone could point me in the right direction, I'd appreciate it.

Answer 1

Try this :

SELECT f.fundname,
       SUM(i.price)
FROM   fund f
       JOIN items i
         ON i.fundid = f.id
GROUP  BY f.fundname  

Answer 2

There's no good reason to do it this way given your table structure however the question does ask about a sub query and the table structure is simplified.

So this will give the same results as straightfoward JOIN/GROUP BY

SELECT f.fundname, 
       coalesce(i.price,0) price
FROM   fund f 
       LEFT JOIN (SELECT fundid, 
                          SUM(price) price 
                   FROM   items i 
                   GROUP  BY fundid) i 
         ON f.fundid = i.fundid 

Note the COALESCE/LEFT JOIN is there in case you want 0 for funds that have no items.

Answer 3

Try this

select fundName,sum(price) as  TotPrice
from Funds f
join Items g on g.id=f.id
group by f.fundName

Answer 4

SELECT f.fundid, f.fundName, SUM(price)
FROM Fund f 
   INNER JOIN ITEMS i ON i.fundId = f.fundId
GROUP BY f.FUNDID

If you have a lot of funds fund Id is probably better to group by