psql -U [username] -W [database]

createuser -S -D -R -P -h localhost -U postgres [username]
dropuser [username]

createdb -O [owner] -h localhost [dbname]

psql -U [username] -W [dbname] < dump.sql
pg_dump -U [username] -h localhost [-t [table]] [dbname] > dump.sql

ALTER TABLE data ALTER COLUMN filename TYPE character varying(255) USING substring(filename from 20);

SELECT foo.xcpr FROM (SELECT a.personid AS xcpr, b.personid AS ycpr FROM examinations AS a LEFT OUTER JOIN person AS b ON a.personid = b.personid) AS foo WHERE foo.ycpr IS NULL;

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