======PostGreSQL======
=====Open sql cli interface======
<code>
psql -U [username] -W [database]
</code>

=====Creating/Deleting users=====
<code>
createuser -S -D -R -P -h localhost -U postgres [username]
dropuser [username]
</code>

=====Creating a database=====
<code>
createdb -O [owner] -h localhost [dbname]
</code>

=====Import/export a database======
<code>
psql -U [username] -W [dbname] < dump.sql
pg_dump -U [username] -h localhost [-t [table]] [dbname] > dump.sql
</code>

=====Cut prefix from table=====
<code>
ALTER TABLE data ALTER COLUMN filename TYPE character varying(255) USING substring(filename from 20);
</code>

=====Find missing foreign key values=====
<code>
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;
</code>

=====Disable pager (less/more) in psql=====
<code>
\pset pager
</code>