Some useful Oracle functions

nvl(expr1, expr2)
if expr1 is null, return expr2. Otherwise, return expr1

nvl(select * from bs_table, 'No data in table')

nvl2(expr1, expr2,expr3)
if expr1 is null, return expr2. Otherwise, return expr3.

nvl2(select * from bs_table where bsname='Bob', 'Bob has no records', 'Records found for Bob')

decode(expr, result1, replace1, result2, replace2, ... [default])
Evaluate expr, if it equals result1, return replace1 instead, etc. If it doesn't match, return default. If no default given, return null.

SELECT DECODE(mydatacolumn,
   'TRUE', 'yes',
   'FALSE', 'no',
   'n/a')

   FROM vmyview b WHERE
      b.someid=62 AND b.otherid=2516 AND b.personid=20
     AND ROWNUM<2

RTRIM(expr, string)
Trims the contents of string from the end of expr. You can use this like NVL with more complicated expressions.

RTRIM('Bscolumn: ' || select bscolumn from bstable, 'Bscolumn: ')

Will return Bscolumn: <query results here> or null.