自然加入mysql 5.6

Question

I would like to see how many medals a country have won. So I decide to combine the tables www_result and www_country. They have the attribute country_id in common. This is my code so far but I get syntax errors, and I can't seem to find the reason.

SELECT * FROM www_results WHERE position = 1 OR position = 2 OR position = 3
NATURAL JOIN 
www_countries;

Thank you in advance

Answer 1

You just have things in the wrong order, do the JOINs then apply the WHERE clause...

You should also specify which table you are referring to when referencing a field name. It's not always necessary but makes it more readable and less prone to bugs.

SELECT
    *
FROM
    www_results
NATURAL JOIN 
    www_countries
WHERE
    www_results.position IN (1, 2, 3)
;

I also actually recommend against NATURAL JOIN any way. If you incidentally have fields with the same name, you get unwanted behaviour. I would use explicit INNER JOIN s.

SELECT
    *
FROM
    www_results
INNER JOIN 
    www_countries
        ON  www_results.country_id = www_countries.country_id
        --  Replace the "country_id" with whatever field you want to join on
WHERE
    www_results.position IN (1, 2, 3)
;