performing a SUM() in sub-query in mysql

Question

I have two tables that have this design

Invoices
-------
invoice_id
is_delivered

Data => (1, 'yes')

Invoice_products
----------------
ip_id
invoice_id
product_id
price

Data=> (1,1,1,5000), (2,1,2,7000)

Now what I want is all the columns of Invoices table and sum of prices in the other table. Something like this

invoice_id = 1
is_delivered = 'yes'
total = 12000

I tried this but the result wasn't correct.

SELECT * FROM invoices i INNER JOIN (SELECT invoice_id, SUM(price) AS total FROM invoice_products p ) AS t ON t.invoice_id = i.invoice_id;

I am not very good in mysql but I tried. Can someone care to answer with explanation?

Answer 1

You have some syntax errors, and you don't need sub-query.
You can just select all from invoice_products and calculate SUM - it is easy to do. You have already done it, but don't miss GROUP clause, it will calculate sums accordingly to distinct invoice_id . If you don't need it - just omit groub clause.
After that you just need join invoices table to get some additional information from this table.

The final result will look like this:

SELECT i.invoice_id, i.is_delivered, p.invoice_id, SUM(p.price) AS total
FROM invoice_products AS p 
INNER JOIN invoices AS i ON p.invoice_id = i.invoice_id
GROUP BY p.invoice_id;