Php 联合所有-联合如何限制为1
正在尝试限制每行。。。 在我的查询中,我得到了结果和结果的图像,但是如果有,例如: 会员有2张图片,它将显示两张图片,如果ttimages有30张图片,它将显示30张图片等 我想要达到的是每个结果的极限。。。 用一张图片显示表中的一个结果,而不是x数量,从而得出图像表中有多少张图片 这是sqlPhp 联合所有-联合如何限制为1,php,mysql,Php,Mysql,正在尝试限制每行。。。 在我的查询中,我得到了结果和结果的图像,但是如果有,例如: 会员有2张图片,它将显示两张图片,如果ttimages有30张图片,它将显示30张图片等 我想要达到的是每个结果的极限。。。 用一张图片显示表中的一个结果,而不是x数量,从而得出图像表中有多少张图片 这是sql $sql = " SELECT DISTINCT members.lastlogin as timeline_date, members.memusername as timeline_title, m
$sql = "
SELECT DISTINCT members.lastlogin as timeline_date, members.memusername as
timeline_title, members.town as timeline_body, memberimages.images as
timeline_img FROM members JOIN memberimages ON members.memid =
memberimages.memid
UNION ALL
SELECT DISTINCT ttages.dateadded as timeline_date, ttages.title as
timeline_title, ttages.body as timeline_body, ttages_images.image as
timeline_img FROM ttages JOIN ttages_images ON ttages.agesid =
ttages_images.ageid
UNION ALL
SELECT DISTINCT sellit_listings.dateadded as timeline_date,
sellit_listings.sittitlename as timeline_title, sellit_listings.sitcontent as
timeline_body, sellit_images.images as timeline_img FROM sellit_listings JOIN
sellit_images ON sellit_listings.listid = sellit_images.listid
UNION ALL
SELECT DISTINCT property_listings.dateadded as timeline_date,
property_listings.paddress as timeline_title, property_listings.plistdiscript
as timeline_body, property_images.image as timeline_img FROM
property_listings JOIN property_images ON property_listings.propid =
property_images.propid
UNION ALL
SELECT DISTINCT event_listings.dateadded as timeline_date,
event_listings.eventtitle as timeline_title, event_listings.eventdescript as
timeline_body, event_images.image as timeline_img FROM event_listings JOIN
event_images ON event_listings.eventid = event_images.eventid
ORDER BY timeline_date DESC LIMIT 70";
如果您希望每个成员、ttage等有一个结果行,请按它们分组:
SELECT
m.lastlogin as timeline_date,
m.memusername as timeline_title,
m.town as timeline_body,
MIN(mi.images) as timeline_img
FROM members m
JOIN memberimages mi ON m.memid = mi.memid
GROUP BY m.memid
UNION ALL
...
这是标准的SQL。一些DBMS可能需要在所有列上使用伪聚合函数(即
MIN(m.lastlogin)
而不是m.lastlogin
等),或者将它们放在GROUP BY子句中。根据标签,它似乎是MySQL。非常感谢:)