Question

I need to join two tables:

countries table

country|lang1|lang2|lang3|lang4
Canada |1    |2    |NULL |NULL
US     |1    |NULL |NULL |NULL

and

languages table

id|language
1 |English
2 |French

I want to return the values for both rows in my countries table, with the language names.

How do I do that?

I tried:

SELECT * FROM en_countries LEFT JOIN all_languages 
ON (all_languages.id = en_countries.lang1 AND all_languages.id = en_countries.lang2)

but that doesn’t give me the language names. How do I do this?

If someone could give me this in Active Record format, that would be a bonus. I’m doing this for CodeIgniter.

Answer 1

I think the issue here is with (all_languages.id = en_countries.lang1 AND all_languages.id = en_countries.lang2)


rather try

SELECT * FROM en_countries LEFT JOIN all_languages 
ON (all_languages.id = en_countries.lang1 OR all_languages.id = en_countries.lang2)

The ‘and’ implies that one language should be the first and second language of a country, replacing it with ‘or’ may do the trick