How: making column value as column of select statement

Question

Hi
Quickly I have searched in this forum for following solution but not able to find it.
I need to make a query in such a way that the value of one column in one table should act as a column-name of another table
Eg:-
tab1
col1,col2,*col3*,col4
tab2
col11 col22 col33 col44
row1 a b col3 d
row2 aa bb cc dd
So the query should be something like --- in row2 if the value is col3 then from tab1 I should pick the col3 in select statement (basically there will be some join in tab1 and tab2 )
Hope I am able to make u all understand my query.
regards

Answer 1

Hi all,
Sorry for late response.Just now I checked all the replies.
Actually I tried in this way.
CREATE OR REPLACE function Proc_caption (in_tan varchar2, in_order in number)
return varchar2
is
d varchar2(100) ;
begin
SELECT col1 into d
from tab1
Where
col2 = in_tanid
AND col3 = 'Y'
AND col4 = in_order ;
return d ;
Exception
WHen No_DATA_FOund then
return 'N' ;
end ;
create or replace procedure proc_generate_view(in_tan varchar2, in_soc varchar2)
is
x varchar2(2000);
v4 varchar2(50) ;
v5 varchar2(50) ;
cnt number ;
begin
v4:= PROC_Caption (in_tan,4) ;
v5:= PROC_Caption (in_tan,5) ;
x := ' Create view v_generate as '
|| ' SELECT a , b, c, d ' ;
if v4 <> 'N' THEN
x := x || ' , ' || PROC_Caption (in_tan,4) || ' as Caption4 ' ;
end if;
if v5 <> 'N' THEN
x := x || ' , ' || PROC_Caption (in_tan,5) || ' as Caption5 ' ;
end if;
x := x || ' FROM tab2 WHERE col1 = ''' || in_socid || ''''
|| ' AND col2 = ''' || in_tan || '''' ;
select count(1) into cnt from USER_OBJECTS where OBJECT_NAME = 'V_GENERATE'
and OBJECT_TYPE = 'VIEW' ;
if cnt > 0 then
EXECUTE IMMEDIATE ' DROP view V_GENERATE' ;
END IF ;
execute immediate x ;
end ;
NOTE:- I have just renamed the table name and column names in order to make it non confedential...
I have created this successfully with actual table name and column names and able to get the result as per my requirement.
regards