QUERY: SELECT 'this is a text string'::text = 'this is a text string'::text AS true;
true
----
t   
(1 row)

QUERY: SELECT 'this is a text string'::text = 'this is a text strin'::text AS false;
false
-----
f    
(1 row)

QUERY: CREATE TABLE TEXT_TBL (f1 text);
QUERY: INSERT INTO TEXT_TBL VALUES ('doh!');
QUERY: INSERT INTO TEXT_TBL VALUES ('hi de ho neighbor');
QUERY: SELECT '' AS two, * FROM TEXT_TBL;
two|f1               
---+-----------------
   |doh!             
   |hi de ho neighbor
(2 rows)