根据MySQL和PHP中其他表的列中的最高值选择行

Question

I'm pants at MySQL, so I really need some help with this, please:

I have a table like:

Pizza              Votes
------------------------
Margherita         1
Pepperoni          7
Sloppy Giuseppe    3

And an other table like:

ID    Pizza              Recipe                         Votes
-------------------------------------------------------------
1     Margherita         Jamie Oliver                   1
2     Pepperoni          Hugh Fearnley Whittingstall    7
3     Sloppy Giuseppe    Gino D'Acampo                  3
4     Margherita         Jamie Oliver                   1
5     Pepperoni          Jamie Oliver                   7
6     Sloppy Giuseppe    Jamie Oliver                   3
7     Sloppy Giuseppe    Hugh Fearnley Whittingstall    3

Notice in the first table, the Pepperoni pizza has the most votes, so I'd like to get the rows from the second table WHERE the Pizza column contains "Pepperoni".

In pseudo-code: SELECT * FROM the second table WHERE the Pizza column = the pizza from the first table with the most votes

So far I have this: 'SELECT * FROM pp_pizzas INNER JOIN pp_recipes ON pp_pizzas.pizza = pp_recipes.pizza'

I really don't understand all this MySQL stuff so if I could ask for an explanation as well as a pointer/answer I'd be very grateful, just so I can learn for next time!

Thank you all so much!

Answer 1

There are a lot of ways to do this, but for such a simple query (and for clarity) I'd go with a subquery rather than a join. Something like:

SELECT * FROM `pp_recipes` WHERE pp_recipes.pizza = (SELECT `pizza` FROM pp_pizzas ORDER BY votes DESC LIMIT 1);

The subquery returns only one column from one row (Pepperoni) which is then used as a condition in the primary query.

Answer 2

You could try:

SELECT * FROM pp_recipes
WHERE Pizza = 
    (SELECT Pizza FROM pp_pizzas
     ORDER BY Votes DESC LIMIT 1)

You could also try:

SELECT * FROM pp_recipes
WHERE Votes = (SELECT MAX(Votes) FROM pp_recipes)

Answer 3

If you are looking to catch all the records from the second table you must use a LEFT JOIN in place of INNER JOIN.

Try this one, and let me know if is what you need :

SELECT * 
FROM 
  pp_pizzas 
LEFT JOIN 
  pp_recipes 
ON pp_pizzas.pizza = pp_recipes.pizza