SQL SELECT with multiple tables and SUM

Question

I have used this forum for a while now to find answers to some SQL related questions. Now it's time to ask a question I have tried to figure out for some time now.

I have two tables (product and source).

I would like to create a SQL SELECT to retrieve a list of records from source and one additional record from product (a SUM of price). The table I would like to see should look something like this:

source.source_id | source.location | source.source_name | source.source_description | source.source_date | source.price | SUM(product.price) | SUM(product.price) WHERE product.quantity < 1 (this last column is where I get stuck).

source.location and product.location are linked.

This code works and give the result I want:

SELECT s.source_id
    , s.location
    , s.source_name
    , s.source_description
    , s.source_date
    , s.source_price
    , p2.Total
    , sum(p1.price) as SumProductSold
FROM source s
JOIN product p1
    on s.location = p1.location
JOIN
(
    SELECT location, sum(price) as Total
    FROM product
    GROUP BY location
) p2
    on s.location = p2.location
WHERE p1.quantity < 1
GROUP BY s.source_id, s.location, s.source_name
    , s.source_description, s.source_date, s.source_price, p2.Total

Thank you bluefeet!!

Solution

without a whole lot of details your can do something like this:

SELECT s.source_id
    , s.location
    , s.source_name
    , s.source_description
    , s.source_date
    , s.price
    , sum(p.price) as SumProductPrice
    , sum(p.location) as SumProductLocation
FROM source S
JOIN product p
    on S.location = p.location
WHERE p.quantity < 1
GROUP BY s.source_id, s.location, s.source_name
    , s.source_description, s.source_date, s.price

if you post more details, then the query can be fine-tuned.

EDIT:

you can join on the products table a second time to get the total for the location:

SELECT s.source_id
    , s.location
    , s.source_name
    , s.source_description
    , s.source_date
    , s.price
    , sum(p1.price) as SumProductPrice
    , p2.Total
FROM source S
JOIN product p1
    on S.location = p1.location
JOIN
(
    SELECT location, sum(price) as Total
    FROM product
    WHERE quantity < 1
    GROUP BY location
) p2
    on S.location = p2.location
WHERE p1.quantity < 1
GROUP BY s.source_id, s.location, s.source_name
    , s.source_description, s.source_date, s.price, p2.Total

Comments

[Hans Lernestål]

I am storing information on purchased products in my source table. I am able to list all the information from this table but I would like to have an additional column (the SUM of sold product).The link is the location id (source.location and product.location).

[Taryn]

is the query I suggested not giving you the result you want? if not, then what appears to be wrong?

[Hans Lernestål]

I get an error: #1054 - Unknown column 'source.location' in 'field list'

[Taryn]

can you post your query that you are running?

[Hans Lernestål]

SELECT s.source_id , s.location , s.source_name , s.source_description , s.source_date , s.source_price , sum(p.price) as SumProductPrice , sum(p.location) as SumProductLocation FROM source s JOIN product p on s.location = p.location WHERE p.quantity < 1 GROUP BY s.source_id , s.location , s.source_name , s.source_description , s.source_date , s.source_price

[Hans Lernestål]

I get a list now, but the last column is not correct yet. It should be showing the sum of the sold products that are connected to the location/source. Thanks for your input.

[Hans Lernestål]

OK, but I get an error #1054 - Unknown column 't.price' in 'field list'. Is this the product.price or the source.price?

[Hans Lernestål]

Now the SQL goes through but with an empty result. Tricky.

[Taryn]

if you run the inner subquery, do you get results?

[Hans Lernestål]

Yes, i get a list from this query: SELECT location, sum(price) as Total FROM product WHERE quantity < 1 GROUP BY location

[Hans Lernestål]

I get the flowing error on this: #1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '[Price1], SUM(CASE WHEN product.quantity < 1 THEN product.price ELSE 0 E' at line 7

[Hans Lernestål]

I have tried the whole string again and SumProductTotal and Total are the same. One should be the total of all products with a specific location and one should be the total of all products with quantity <1 with the same location.