PostgreSQL: Row count over time -

i have simple mysql sql-script, outputs me row count on time specific table (based on datetime field in table)

select concat('m-', s.label)      , s.cnt      , @tot := @tot + s.cnt  running_subtotal   ( select date_format(t.created,'%y-%m') `label`               , count(t.id) cnt            `templates` t           group `label`           order `label`        ) s  cross   join ( select @tot := 0 ) 

now want migrate postgresql, have no idea how migrate variables pg-based syntax.

the inner statement is, of course, no problem:

select to_char(t.created,'yyyy-mm') label               , count(t.id) cnt            templates t           group label           order label 

anyone here, can me variable-part?

here's simple table data:

create table "templates" (     "id" bigserial,     "title" varchar(2048) default null::character varying,     "created" timestamp,     primary key ("id") );  insert templates(title, created) values('test', '2011-03-01'); insert templates(title, created) values('test 2', '2011-03-02'); insert templates(title, created) values('test 3', '2011-03-03'); insert templates(title, created) values('test 4', '2011-03-04'); insert templates(title, created) values('test 5', '2011-03-05'); insert templates(title, created) values('test 6', '2011-04-01'); insert templates(title, created) values('test 7', '2011-04-02'); insert templates(title, created) values('test 8', '2011-04-03'); insert templates(title, created) values('test 9', '2011-04-04'); insert templates(title, created) values('test 10', '2011-04-05'); … // 300 more 2011-05 

the example output of query (based on records "created"-column) is:

 m-11-03:   5   5 m-11-04:   5  10 (5 + 5) m-11-05: 300 310 (5 + 5 + 300) 

(this spin off of table statistics (aka row count) on time)

this works:

select month, hm, sum(hm) over(order month) from( select to_char(created, 'm-yyyy-mm') month, count(*) hm templates group 1 ) x order month 

http://www.sqlfiddle.com/#!15/eb08a/14