Min() with INNER JOIN and Full-text-search - php

Question

So Ive got the following Query to work just fine, searching for 'test*' in 'products_desc' column and fetching all its prices in the 'prices' table.
SELECT products.id, prices.price, products.product_desc FROM products
INNER JOIN prices
ON prices.product_id = products.id
WHERE
MATCH (products.product_desc) AGAINST ('test*' IN BOOLEAN MODE)
Although the 'prices' table consists of multiple prices per product and I only want to fetch the lowest one to each product. I've previously filtered the prices using
INNER JOIN (
SELECT min(price) as price, prices.product_number as product_number FROM prices
WHERE prices.product_number LIKE'".$q."%'
GROUP BY prices.product_number
) min_prices
on prices.price = min_prices.price
and prices.product_number = min_prices.product_number
but this was when I used products_numbers within the prices table (now there is just a product_id-column.
Products
id | product_desc
----------------------------------------
1 | product1
2 | product2
Prices
id | product_id | price
------------------------------------------------
1 | 1 | 312
2 | 1 | 219
3 | 2 | 312
4 | 2 | 111
Also, the table consists of 10+ million rows so, efficiency matters a lot :)
EDIT
What if I need to access value of columns on the min(prices.price) row?
SELECT products.id, MIN(prices.price) as prices_price, prices.id as prices_id, products.product_desc, products.product_number, prices.supplier_id, suppliers.name FROM products
INNER JOIN prices
ON prices.product_id = products.id
INNER JOIN suppliers
ON prices.supplier_id = suppliers.id
WHERE
MATCH (products.product_desc) AGAINST ('test*' IN BOOLEAN MODE)
GROUP BY prices.product_id
The above returns the lowest price per product but also the wrong value in the other columns?

Answer 1

You can use GROUP BY for this, with MIN() group by function.
GROUP BY is used to group values from a column, and perform calculations on column.
In our case we want to group the result by product_id as it's repeating in second table and perform calculation (min()) on price column of second table.
This is how your Query would look like:
SELECT products.id, MIN(prices.price), products.product_desc FROM products
INNER JOIN prices
ON prices.product_id = products.id
WHERE
MATCH (products.product_desc) AGAINST ('test*' IN BOOLEAN MODE)
GROUP BY prices.product_id