-- -- TEXT -- SELECT text 'this is a text string' = text 'this is a text string' AS true; SELECT text 'this is a text string' = text 'this is a text strin' AS false; CREATE TABLE TEXT_TBL (f1 text); INSERT INTO TEXT_TBL VALUES ('doh!'); INSERT INTO TEXT_TBL VALUES ('hi de ho neighbor'); SELECT '' AS two, * FROM TEXT_TBL; -- As of 8.3 we have removed most implicit casts to text, so that for example -- this no longer works: select length(42); -- But as a special exception for usability's sake, we still allow implicit -- casting to text in concatenations, so long as the other input is text or -- an unknown literal. So these work: select 'four: '::text || 2+2; select 'four: ' || 2+2; -- but not this: select 3 || 4.0; /* * string functions */ select concat('one'); select concat(1,2,3,'hello',true, false, to_date('20100309','YYYYMMDD')); select concat_ws('#','one'); select concat_ws('#',1,2,3,'hello',true, false, to_date('20100309','YYYYMMDD')); select concat_ws(',',10,20,null,30); select concat_ws('',10,20,null,30); select concat_ws(NULL,10,20,null,30) is null; select reverse('abcde'); select i, left('ahoj', i), right('ahoj', i) from generate_series(-5, 5) t(i) order by i;