[GENERAL] Create table if not exists ... how ??

[Jennifer Trey]

I can't figure out the correct syntax...

I have this, but it just keeps complaining about the IF

IF NOT EXISTS (SELECT table_name FROM information_schema.tables where
table_name = 'post_codes')

THEN

CREATE TABLE post_codes
(
  area character varying(10) NOT NULL,
  district character varying(10) NOT NULL,
  sector character varying(10) NOT NULL,
  CONSTRAINT post_codes_pkey PRIMARY KEY (area, district, sector)
)
WITH (
  OIDS=FALSE
);
ALTER TABLE post_codes OWNER TO postgres;

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
- - - - - - - - - -

ERROR:  syntax error at or near "IF"
LINE 1: IF NOT EXISTS (SELECT table_name FROM information_schema.tab...
        ^

********** Error **********

ERROR: syntax error at or near "IF"
SQL state: 42601
Character: 1


How should this be written ?

Thanks, Jen