Query for lowest price for product in same row I have two tables: first for products and second for prices. 



I need to calculate and display the minimum price from all 5 prices for one product.
I already have query to select five prices and dont know what to do next:

SELECT 
    wp_prices.price_one, 
    wp_prices.price_two, 
    wp_prices.price_three, 
    wp_prices.price_four, 
    wp_prices.price_five 
FROM wp_products
JOIN wp_prices ON wp_products.id = wp_prices.product_id
WHERE wp_prices.product_id = ' . $current_product_id . '
Of course your data is denormalized, otherwise it would be a simple MIN(price) :-)

If you got luck your DBMS supports a LEAST function:

LEAST(price_one,price_two,price_three,price_four,price_five),


A huge CASE is supported in every DBMS:

CASE
  WHEN price_one &lt;= price_two
   AND price_one &lt;= price_three
   AND price_one &lt;= price_four
   AND price_one &lt;= price_five
  THEN price_one

  WHEN price_two &lt;= price_three
   AND price_two &lt;= price_four
   AND price_two &lt;= price_five
  THEN price_two

  WHEN price_three &lt;= price_four
   AND price_three &lt;= price_five
  THEN price_three

  WHEN price_four &lt;= price_five
  THEN price_four

  ELSE price_five
END


Hopefully there are no NULLs...