SELECT max(DECODE (currency, 'USD', rate)) USD,
       max(DECODE (currency, 'EUR', rate)) EUR,
       max(DECODE (currency, 'GBP', rate)) GBP
  FROM exchange;

USD	EUR	GBP
1	2	3

select max(case 
                 when currency = 'USD' then rate
                 else null
            end) USD,
		max(case  
                 when currency ='EUR' then rate
                 else null
            end) EUR,
		max(case 
                 when currency ='GBP' then rate
                 else null
            end) GBP
from exchange;

USD	EUR	GBP
1	2	3

SELECT   object_type, 
	 SUM (DECODE (owner, 'SCOTT', 1, 0)) scott_count,
	 SUM (DECODE (owner, 'TOAD', 1, 0)) toad_count
    FROM all_objects
   WHERE owner IN ('SCOTT', 'TOAD')
GROUP BY object_type;

OBJECT_TYPE	SCOTT_COUNT  TOAD_COUNT
--------------- -----------  ----------
INDEX		2		7
PACKAGE		0		1
PACKAGE BODY	0		1
SEQUENCE	0		1
TABLE		5		7
TRIGGER		1		0
VIEW		0		2