mysql - JOIN mysql if else 语句

Question

这是一个奇怪的条件语句 - 我不确定它是否可能。

我有一个 MYSQL 查询:

SELECT 
cute_news.title, cute_news.id, cute_news.avatar, cute_news.category,cute_news.date, cute_fields.YouTubeTN, cute_fields.alternate_title, cute_fields.NewsSource, cute_fields.alternate_url, cute_fields.cf_id 
FROM cute_news, cute_fields 
WHERE 
YEAR(FROM_UNIXTIME(cute_news.date)) = '2007' AND 
cute_fields.cf_id = cute_news.cf_id AND 
FIND_IN_SET ('10', cute_news.category) 
ORDER BY cute_news.date DESC

我的问题是我想要:

IF ( cute_fields.cf_id = cute_news.cf_id )THEN
{  SELECT 
cute_news.title, cute_news.id, cute_news.avatar, cute_news.category,cute_news.date, cute_fields.YouTubeTN, cute_fields.alternate_title, cute_fields.NewsSource, cute_fields.alternate_url, cute_fields.cf_id 
FROM cute_news, cute_fields 
WHERE 
YEAR(FROM_UNIXTIME(cute_news.date)) = '2007' AND 
cute_fields.cf_id = cute_news.cf_id AND 
FIND_IN_SET ('10', cute_news.category) 
ORDER BY cute_news.date DESC }
ELSE {
 SELECT 
cute_news.title, cute_news.id, cute_news.avatar, cute_news.category,cute_news.date 
FROM cute_news 
WHERE 
YEAR(FROM_UNIXTIME(cute_news.date)) = '2007' AND 
FIND_IN_SET ('10', cute_news.category) 
ORDER BY cute_news.date DESC }
ORDER BY..

实际执行此操作最困难。也许这是不可能的。预先感谢 NINJAS!

Answer 1

如果我清楚地理解您的要求，您需要Left Join。如果将为您的 Else 部分提供 NULL 。

SELECT 
cute_news.title, cute_news.id, cute_news.avatar, cute_news.category,cute_news.date, 
cute_fields.YouTubeTN, cute_fields.alternate_title, cute_fields.NewsSource, cute_fields.alternate_url, cute_fields.cf_id 
FROM cute_news n
LEFT JOIN 
cute_fields f
ON f.cf_id = n.cf_id
WHERE 
YEAR(FROM_UNIXTIME(cute_news.date)) = '2007' AND 
FIND_IN_SET ('10', cute_news.category) 
ORDER BY cute_news.date DESC