Help need to generate query

Question

Hi,
I have the following info from a table named X.
Col1 Col2 Col3 Col4
IT01 20 01 X
IT01 20 50 X
IT01 30 01 X
IT01 30 50 X
If Col4 has value ‘X’ all the 4 combinations of Col2 & Col3, The result should be displayed as
Col1 Col4
IT01 X
If the actual values are like
Col1 Col2 Col3 Col4
IT01 20 01 X
IT01 20 50 X
IT01 30 01 X
IT01 30 50 Y
Then The result should be displayed as
Col1 Col4
IT01 Y
How will generate the query for this?
Thanks,
Titus Thomas
Edited by: Titus Thomas on Apr 20, 2010 2:48 PM

Answer 1

Try this:
with test_tab as (select 'ITO1' Col1, 20 Col2, 01 Col3, 'X' Col4 from dual union all
                  select 'ITO1' Col1, 20 Col2, 50 Col3, 'X' Col4 from dual union all
                  select 'ITO1' Col1, 30 Col2, 01 Col3, 'X' Col4 from dual union all
                  select 'ITO1' Col1, 30 Col2, 50 Col3, 'X' Col4 from dual union all
                  select 'ITO2' Col1, 20 Col2, 01 Col3, 'X' Col4 from dual union all
                  select 'ITO2' Col1, 20 Col2, 50 Col3, 'X' Col4 from dual union all
                  select 'ITO2' Col1, 30 Col2, 01 Col3, 'X' Col4 from dual union all
                  select 'ITO2' Col1, 30 Col2, 50 Col3, 'Y' Col4 from dual)
--- end of mimicking your data; use SQL below:                 
select col1, max(col4) col4
from   test_tab
group by col1;
COL1 COL4
ITO2 Y  
ITO1 X