Subquery error. Help please!!
От | kakerjak |
---|---|
Тема | Subquery error. Help please!! |
Дата | |
Msg-id | 9hdi36$scd$1@news.tht.net обсуждение исходный текст |
Ответы |
Re: Subquery error. Help please!!
Re: Subquery error. Help please!! Re: Subquery error. Help please!! |
Список | pgsql-sql |
Hey all.. Here's the table definition. CREATE TABLE "laboratory" ( "id" "int4" NOT NULL, "subid" "int2" NOT NULL, "name" varchar(30) NOT NULL, CONSTRAINT"laboratory_pkey" PRIMARY KEY ("id", "subid")) The way this table works is that each lab has one ID. If any information is changed(there are actually more fields then what i showed, but they don't affect the problem) then the ID remains the same, but the SUBID gets incremented by 1. Thus, other tables linking to it just need to know the ID and then read the ID with the biggest SUBID to get the most recent record. Now, what I want to do is this. Create a list of all the laboratories using only the most recent record for each (the biggest SUBID for every unique ID). Here's my select statement. SELECT b.id, b.subid, b.name FROM (SELECT c.id, MAX(c.subid) AS subid FROM laboratory AS c GROUP BY id) AS a INNER JOIN laboratory AS b USING id, subid The subquery works on it's own and returns the desired ID, SUBID combinations. But when put into the other query I get parser errors. If the subquery is placed before the JOIN, like it is above, then the error i get says 'parse error at or near "select"' If i flip the subquery around with the laboratory table then i get 'parse error at or near "("' According to the documention online, it seems as if this statement should work. ( http://www.postgresql.org/idocs/index.php?queries.html#QUERIES-FROM ) Any help would be appreciated. TIA kakerjak
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