Denormalizing during select
От | no.spam@address.com |
---|---|
Тема | Denormalizing during select |
Дата | |
Msg-id | u3kk5v4i276aqv2hv22pn6jh4t3a2ev08g@4ax.com обсуждение исходный текст |
Список | pgsql-sql |
I have two tables (A and B) in a one-to-many relationship. When retrieving data from one table (A), I need to denormalize the tables during a select so that values of a column in the many table (B) appear as a list in one field of the output. E.g.: create table one_table ( name varchar(20), age integer, -- constraint one_table_pk primary key (name) ); create table many_table ( name varchar(20), property varchar(15), -- constraint many_table_pk primary key(name, property), constraint many_table_fk foreign key (name) references one_table (name) ); So one_table could contain: name age ---- --- Mickey Mouse 50 Donald Duck 60 Goofy 45 and many_table could contain: name property ---- -------- Mickey Mouse Small Mickey Mouse Black Mickey Mouse Squeaks Donald Duck Quacks The query I'm trying to write would have as output something like: name age properties ---- --- ---------- Mickey Mouse 50 Small, Black, Squeaks DonaldDuck 60 Quacks Goofy 45 <null> Could somebody please help point me in the right direction? I imagine this is a common need... Thanks, ...Edmund.
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