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
