-- Fills in the blanks of the items table by joining each item change record
-- to the previous valid record for the same item, to allow retrival of last "real" price change
select * from (	
	select 
	a.id,
	coalesce(a.priceChange, b.priceChange) as priceChange,
ROW_NUMBER() OVER (PARTITION

select id, priceChange, 
coalesce((
   select priceChange 
   from YourTable b 
   where a.rn > b.rn and a.id = b.id and b.priceChange is not null and a.priceChange is null order by b.rn desc limit 1 ), 
   a.priceChange
) tmp, 
cMonth
from YourTable a order by id, rn

[B]ID    priceChange    Month       rn[/B]
1     100      March 2010         1
1     null     April  2010        2

ON tI.ID = sIi.ID AND tI.RN > sIi.RN

[B]ID    priceChange    Month       rn[/B]
1     100      March 2010  1
1     null     June 2010   2
1     200      July 2010   3
2     520      March

select 
a.id,
coalesce(a.typeName, b.typeName) as typeName
FROM table1 a, table1 b
where a.id = b.id AND b.rn

UPDATE TABLE1 SET COL1 = 123 WHERE COL2 IN (SELECT COL3 FROM TABLE2)