UPDATE

UPDATE T1
  FROM tab1 T1, tab2 T2
   SET c1 = T2.c1                
     , c2 = T2.c2 
 WHERE T1.c3 = T2.c3;

UPDATE tab1 T1
   SET c1 = T2.c1                
     , c2 = T2.c2 
  FROM tab2 T2
 WHERE T1.c3 = T2.c3;

UPDATE t1
  FROM tab1 t1, ( SELECT c1, c2 FROM tab2
                   WHERE c2 > 100 ) t2
   SET c1 = t2.c1
 WHERE t1.c2 = t2.c2;

 UPDATE tab1 t1
   SET c1 = t2.c1
  FROM ( SELECT c1, c2 FROM tab2
          WHERE c2 > 100 ) t2
 WHERE t1.c2 = t2.c2;

UPD employee SET ename = 'Jane'
        WHERE ename = 'John';
COLLECT STAT on employee;

UPDATE employee SET ename = 'Jane'
 WHERE ename = 'John';
ANALYZE employee;