MySQL IF conditions and internationalization
I'm wondering the following, the query below will select the appropriate fields if a language is set.
First question, I need the fields, title, keywords and description from the pages table or, if the language matches and the field is not null the page_langs table. Now I do this with three IF statements, is it possible to do this in a single IF?
Below query works and the array returned is something like this:
Array ( [0] => Array ( [Page] => Array ( [id] => 2 [lft] => 2 [rght] => 7 ) [0] => Array ( [title] => Welcome [keywords] => welcome [description] => welcome ) ) )
So, the id, lft, and rght are 'within the Page (-> pages AS Page) array', the title, keywords and description are outside the Page array, makes sense offcourse, but how do I get those three fields within the Page array, so I can use arr[Page][title] to retrieve the title instead arr[0][title]?
$sql = "SELECT Page.id, Page.lft, Page.rght,
IF (STRCMP(Lang.title, '') AND
!STRCMP(Lang.langident, '{$lang}'), Lang.title, Page.title) AS title,
IF (STRCMP(Lang.keywords, '') AND
!STRCMP(Lang.langident, '{$lang}'), Lang.keywords, Page.keywords) AS keywords,
IF (STRCMP(Lang.description, '') AND
!STRCMP(Lang.langident, '{$lang}'), Lang.description, Page.description) AS description
FROM pages AS Page
LEFT JOIN page_langs AS Lang
ON Lang.parent_id = Page.id AND Lang.langident = '{$lang}'
WHERE Page.id = {$id}开发者_StackOverflow社区"
Any help (suggestions about the query maybe?) appreciated.
I need the fields, title, keywords and description from the pages table or, if the language matches and the field is not null the page_langs table.
SELECT
COALESCE(Lang.title, Page.title) AS title
/* ... etc ... */
FROM
pages AS Page
LEFT JOIN page_langs AS Lang ON Lang.parent_id = Page.id
AND Lang.langident = '{$lang}'
WHERE
Page.id = {$id}
Since you left-join against the page_langs
table with the correct language only, there is no need to check the language code again in the SELECT expression.
If the translation is there, it will be the correct language right away. If the correct language is missing, it will be NULL, hence COALESCE()
is sufficient.
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