How to use the first row function value for the rest of records

Question

Hi all,
I am having a select statement like this. We are calling function enabled for each row. So it is taking
time. As per our bussiness logic, we can use what the function 'enabled' will give for the first row to
other rows also. so that we can avoid calling the function 'enabled' next row onwars.
Before
SELECT
decode(enabled(col1, col2, col3),'TRUE','xxx', col4),
decode(enabled(col1, col2, col3),'TRUE','xxx', col5),
decode(enabled(col1, col2, col3),'TRUE','xxx', col6),
decode(enabled(col1, col2, col3),'TRUE','xxx', col7),
decode(enabled(col1, col2, col3),'TRUE','xxx', col8),
from
table1 t1, table2 t2 where t1.col1 = t2.col1
After
SELECT
decode(enabled(col1, col2, col3),'TRUE','xxx', col4),
decode('true/false','TRUE','xxx', col5), --Here 'true/false' is the first row value after calling the function 'enabled'
decode('true/false','TRUE','xxx', col6),
decode('true/false','TRUE','xxx', col7),
decode('true/false','TRUE','xxx', col8),
from
table1 t1, table2 t2 where t1.col1 = t2.col1
Any thoughts on this, how to implement this logic
Thanks,
Pal

Answer 1

It's not clear where col1, col2, col3... etc. come from, so I've assumed they're in table1.
with table1_X as (select enabled(col1, col2, col3) as enbl
                        ,col1, col2, col3, col4, col5, col6, col7, col8
                  from   table1)
SELECT decode(t1.enbl,'TRUE','xxx', col4)
      ,decode(t1.enbl,'TRUE','xxx', col5)
      ,decode(t1.enbl,'TRUE','xxx', col6),
      ,decode(t1.enbl,'TRUE','xxx', col7),
      ,decode(t1.enbl,'TRUE','xxx', col8),
from   table1_x t1 join table2 t2 on (t1.col1 = t2.col1)p.s. you'd be better leaving out the enabled function altogether and incorporating the logic of the function directly in the SQL, and then you would be avoiding any context switching which will clearly impact performance on any large amount of data.
Edited by: BluShadow on 14-May-2013 08:26