Sql 如何重新编写此查询,以便不排除没有标记的数据?
目前,此查询排除了我的报告中不包含标记的记录。有人能帮我更改此查询,使其返回所有记录(带或不带标记)Sql 如何重新编写此查询,以便不排除没有标记的数据?,sql,postgresql,Sql,Postgresql,目前,此查询排除了我的报告中不包含标记的记录。有人能帮我更改此查询,使其返回所有记录(带或不带标记) SELECT cmsdocument.internaldocid, cmsdocument.documentid, cmsdocument.versionid, cmsdocversion.title, string_agg(cmstag.tagname, ',') FROM public.cmsobjecttag, public.cmstag, public.
SELECT
cmsdocument.internaldocid,
cmsdocument.documentid,
cmsdocument.versionid,
cmsdocversion.title,
string_agg(cmstag.tagname, ',')
FROM
public.cmsobjecttag,
public.cmstag,
public.cmsdocument,
public.cmsdocversion,
public.cmsuser
WHERE
cmsobjecttag.tagid = cmstag.tagid AND
cmsobjecttag.objectid = cmsdocument.internaldocid AND
cmsdocument.internaldocid = cmsdocversion.internaldocid AND
cmsdocument.userid = cmsuser.userid AND
cmsdocversion.state = 'published' AND
cmsobjecttag.objecttype = '102'
GROUP BY
cmsdocument.internaldocid,
cmsdocument.documentid,
cmsdocument.versionid,
cmsdocversion.title;
正如@notulysses所评论的,您应该使用外部连接。例如(未经测试):
您是否尝试过删除“cmsobjecttag.tagid=cmstag.tagid和”?您可以对
public.cmstag
使用left-outer-join
而不是implicitinternal-join
。您是否可以在@Pavel Gatnar更具体一点?是否存在语法错误或没有标记的文档仍被排除在外?更新为为为public.cmstg
添加LEFT JOIN
,并将ot.objecttype='102'
添加到联接条件中。是的,正如您所看到的,我也做了相同的操作。这个答案有什么悬而未决的问题吗?谢谢@bdunn和其他人-这很有效。
SELECT
d.internaldocid,
d.documentid,
d.versionid,
dv.title,
string_agg(t.tagname, ',')
FROM
public.cmsdocument d
JOIN public.cmsdocversion dv ON d.internaldocid = dv.internaldocid AND dv.state = 'published'
JOIN public.cmsuser u ON d.userid = u.userid
LEFT JOIN public.cmsobjecttag ot ON d.internaldocid = ot.objectid AND ot.objecttype = '102'
LEFT JOIN public.cmstag t ON t.tagid = ot.tagid
GROUP BY
d.internaldocid,
d.documentid,
d.versionid,
dv.title;