Question

我必须在Joomla网站上编辑下面的查询。这个查询是如此缓慢和困难，它经常杀死服务器，我得到错误网关超时..请帮助我编辑它，如果可能，以避免这么多左连接，因为我认为使它如此“沉重”..查询是：

SELECT 
o.*, o.price AS value, c.name AS catname, g.title AS groupname, u.name AS editor, 
u.id AS userid, u.block as blockuser, t.name as typename, t.id as typeid, 
a.name as agentname, a.id as agentid, image.path as imagepath, 
image.fname as imagefilename, image.type as imagetype, l.title AS language_title,
l.image AS langImage, u.name AS editor     
FROM (mytable_estateagent AS o, mytable_estateagent_categories AS c ) 
LEFT JOIN ( 
    SELECT * FROM mytable_estateagent_images AS img 
        WHERE 1 AND (img.type = '.jpg' OR img.type = '.gif' OR img.type = '.png') 
        AND ( img.ordering= 1 or img.ordering= 0 ) AND img.published = 1 
        GROUP BY img.objid 
    ) 
as image ON (image.objid = o.id)    
LEFT JOIN mytable_estateagent_type AS t ON (o.type = t.id)        
LEFT JOIN mytable_languages AS l ON l.lang_code = o.language     
LEFT JOIN mytable_estateagent_agents AS a ON (o.agent = a.id) 
LEFT JOIN mytable_viewlevels AS g ON (g.id = o.access) 
LEFT JOIN mytable_users AS u ON (u.id = o.created_by) 
LEFT JOIN mytable_users AS uc ON uc.id = o.checked_out 
WHERE 1 AND (c.id = o.cat) ORDER BY id ASC

Answer 1

请参阅上面的评论，但请注意此位（已编辑）......

SELECT o.*
...    
LEFT JOIN
 (  SELECT DISTINCT img.objid 
       FROM mytable_estateagent_images img 
      WHERE img.type IN('.jpg','.gif','.png') 
        AND img.ordering IN(1,0) 
        AND img.published = 1
 ) image 
ON image.objid = o.id

...可以（进一步）重写如下......

SELECT DISTINCT o.*
... 
LEFT 
JOIN mytable_estateagent_images image
  ON image.objid
 AND image.type IN('.jpg','.gif','.png') 
 AND image.ordering IN(1,0) 
 AND image.published = 1
...

如何编辑杀死服务器的这个非常复杂的Joomla查询

1 个答案: