MySQL simple localization - mysql

Question

Im trying to make some sort of localization in my DB.
For example I have 3 tables(img 1). Languages table contains different languages. Localization table has 3 fields: "id" - id of the string, 'language' - language of the string(id and language are my primary key), 'value' - localized string. tableOne has 'id', 'Col1' and 'Col2' - these fields contain IDs of the localizeable strings.
So after localizing I expect to get one of green tables instead of original(depending on a language parameter).
I've made it this way and it works, but I'd like to know is there any other better way to make it because now I have to create INNER JOIN block for each column, which must be localized. Im just scared that it will be very very slow.
I tried to create a temporary table to select all records of the required language and then i was doing the same. Inner joins, but searches should be performed only among the records of one language. But its not working because i still had to use multiple inner joins with that temp table which is impossible.
SELECT
`One`.`id` AS 'id',
`loc1`.`value` AS 'Col1',
`loc2`.`value` AS 'Col2'
FROM
`tableOne` AS `One`
INNER JOIN
`localization` AS `loc1`
ON `loc1`.`id` = `One.Col1`
AND `loc1`.`language` = 'en'
INNER JOIN
`localization` AS `loc2`
ON `loc2`.`id` = `One.Col2`
AND `loc2`.`language` = 'en'
img 1

Answer 1

If you want to reduce the number of JOINS needed, try displaying the values in rows instead of columns. You could do so like this:
SET #lang := 'en';
SELECT 1, tmp.value
FROM(
SELECT value
FROM localization
WHERE language = #lang AND id IN(543, 345)) tmp;
I first set a language parameter, and then I pull all values for that language from the localization table, using the ids inside an IN operator. You'll get results like this:
| 1 | one |
| 1 | two |
If you have to use the format given in the first table, try doing one inner join where you pull for the specific language and ids like this:
SELECT t1.id, t1.col1, t1.col2,
CASE WHEN l.id = t1.col1 THEN l.value ELSE null END AS col1Value,
CASE WHEN l.id = t1.col2 THEN l.value ELSE null END AS col2Value
FROM firstTable t1
JOIN localization l ON l.id IN (t1.col1, t1.col2) AND l.language = #lang;
Unfortunately, this won't give you the final solution, it will give you values like:
| 1 | 543 | 345 | one | null |
| 1 | 543 | 345 | null | two |
To wrap those into one column and remove nulls, just add MAX():
This will run a case statement for each column you have, but it will only have one JOIN and looks a little more manageable:
SELECT t1.id,
MAX(CASE WHEN l.id = t1.col1 THEN l.value ELSE null END) AS col1Value,
MAX(CASE WHEN l.id = t1.col2 THEN l.value ELSE null END) AS col2Value
FROM firstTable t1
JOIN localization l ON l.id IN (t1.col1, t1.col2) AND l.language = #lang
GROUP BY t1.id;
Here is an SQL Fiddle example. I don't think the case blocks will bog you down too much, but let me know how this preforms against your actual database.