mysql left join，这样的query怎么写？

Question

我有

首先:

select url from urls where site = '$value' order by url

第二个:

select id, widget_name from widgets where display_urls LIKE 'urls.url' and is_father=1 order by id

第三:

select id, widget_name from widgets where display_urls RLIKE 'urls.url' and is_father=0 order by id

第四:

select id, widget_name, father_widget from widgets where father_widget = 'widgets.id' order by id

第四个查询只能从第二个查询中获取 widgets.id 第二个和第三个查询从第一个查询中获取 urls.url 的值

如何使用左连接将所有这些写在一个 mysql 查询中？

预先感谢您的回答:)

Answer 1

SELECT  w.id, w.widget_name, c.*
FROM    urls
JOIN    widgets w
ON      w.display_urls LIKE urls.url
        OR w.display_urls RLIKE urls.url
LEFT JOIN
        widgets с
ON      c.father_widget = w.id
        AND w.display_urls LIKE urls.url
        AND w.display_urls NOT RLIKE urls.url
WHERE   site = $value
ORDER BY
        url

这将只为那些 LIKE 但也不 RLIKE 相应 url 的小部件选择子级。