[GENERAL] LEFT JOIN, entry can not be referenced
От | Jan Danielsson |
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Тема | [GENERAL] LEFT JOIN, entry can not be referenced |
Дата | |
Msg-id | 284316f1-8dd4-3b99-742e-a89885cc1ef5@gmail.com обсуждение исходный текст |
Ответы |
Re: [GENERAL] LEFT JOIN, entry can not be referenced
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Список | pgsql-general |
Hello, I'm trying to use LEFT JOIN's in a manner which I imagine is pretty archetypal. In short; I have a table called worklogs which has a few columns that can't be NULL, and a few columns which may reference other tables or will be NULL. If the optional columns are not NULL I want to use their id's to fetch names/titles from other columns. I use the following query to gather a list of the work log rows (this query is much simpler than it looks at first glance; it just has a lot of columns): SELECT wl.ts,wa.name,wl.user_id,u.name,wl.doc_id,d.doc_id,wl.docrev_id,dr.docrev,wl.file_id,f.fname,wl.issue FROM worklogs AS wl, workactions AS wa, users AS u LEFT JOIN documents AS d ON wl.doc_id=d.id LEFT JOIN docrevs AS dr ON wl.docrev_id=dr.id LEFT JOIN files AS f ON wl.file_id=f.id WHERE wl.action_id=wa.id AND wl.user_id=u.id ORDER BY wl.ts DESC; When I run this I get the error: -------------------- ERROR: invalid reference to FROM-clause entry for table "wl" LINE 3: LEFT JOIN documents AS d ON wl.doc_id=d.id ^ HINT: There is an entry for table "wl", but it cannot be referenced from this part of the query. -------------------- This is at the outer bounds of my SQL knowledge; I understand what the error and hint are saying (wl isn't valid in the context of the JOIN), but I'm not sure how to remedy that / how to rephrase the query. ("Dear Diary"-moment: I've had queries in the past which work in postgresql which I couldn't run in sqlite, but this is the first time I can recall where a query works in sqlite but not in postgresql). -- Kind regards, Jan Danielsson
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