Array of arrays in PostgreSQL

Question

I\'m using the %% operator on PostgreSQL\'s hstore type which converts a hstore (key-value type effectively) into an array whose elements alternate {{key, value

Answer 1

PostgreSQL support a multidimensional arrays instead - arrays are relative very special type in relational databases and it is little bit limited against general programming languages. If you need it, you can use a workaround with row arrays:

postgres=# create table fx(a int[]);
CREATE TABLE
postgres=# insert into fx values(array[1,3,4]);
INSERT 0 1
postgres=# insert into fx values(array[6,7]);
INSERT 0 1
postgres=# select array_agg(row(a)) from fx;
            array_agg            
---------------------------------
 {"(\"{1,3,4}\")","(\"{6,7}\")"}
(1 row)