I can only see a LIMIT 1 possible. If someone can come up with LIMIT N on this one, please let us all know.
rolando=# drop table if exists t2; DROP TABLE rolando=# drop table if exists t1; DROP TABLE rolando=# create table t1 ( id int primary key, title varchar(10) ); NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "t1_pkey" for table "t1" CREATE TABLE rolando=# insert into t1 values (1,'abcde'),(2,'fghi'); INSERT 0 2 rolando=# create table t2 (id int primary key,t1id int not null references t1 (id) ,somedate date); NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "t2_pkey" for table "t2" CREATE TABLE rolando=# insert into t2 values rolando-# (1,1,'2010-05-23'), rolando-# (2,1,'2010-05-24'), rolando-# (3,1,'2010-05-25'), rolando-# (4,2,'2010-05-22'), rolando-# (5,2,'2010-05-26'); INSERT 0 5 rolando=# select * from t1; id | title ----+------- 1 | abcde 2 | fghi (2 rows) rolando=# select * from t2; id | t1id | somedate ----+------+------------ 1 | 1 | 2010-05-23 2 | 1 | 2010-05-24 3 | 1 | 2010-05-25 4 | 2 | 2010-05-22 5 | 2 | 2010-05-26 (5 rows) rolando=# select t1.id,t2.id,t2.somedate rolando-# from t1,t2,(select t1id,max(somedate) as somedate from t2 group by t1id) t3 rolando-# where t1.id=t2.t1id rolando-# and t2.somedate=t3.somedate; id | id | somedate ----+----+------------ 1 | 3 | 2010-05-25 2 | 5 | 2010-05-26 (2 rows) Rolando A. Edwards MySQL DBA (CMDBA) 155 Avenue of the Americas, Fifth Floor New York, NY 10013 212-625-5307 (Work) 201-660-3221 (Cell) AIM & Skype : RolandoLogicWorx redwa...@logicworks.net http://www.linkedin.com/in/rolandoedwards -----Original Message----- From: pgsql-sql-ow...@postgresql.org [mailto:pgsql-sql-ow...@postgresql.org] On Behalf Of Michele Petrazzo - Unipex Sent: Wednesday, May 26, 2010 1:35 PM To: pgsql-sql@postgresql.org Subject: [SQL] inner join and limit Hi list, I have two table that are so represented: t1: id int primary key ... other t2: id int primary key t1id int fk(t1.id) somedate date ... other data t1: 1 | abcde 2 | fghi data t2: 1 | 1 | 2010-05-23 2 | 1 | 2010-05-24 3 | 1 | 2010-05-25 4 | 2 | 2010-05-22 5 | 2 | 2010-05-26 I'm trying to create a query where the data replied are: join t1 with t2 and return only the LIMIT 1 (or N) of the t2, with date order (of t2). Data should be: t1.id | t2.id | t2,somedate 1 | 3 | 2010-05-25 2 | 5 | 2010-05-26 As said, I'm trying, but without success... Can be done for you? Thanks, Michele -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
