Any one knowing abut the centura sql windos plz solve this prob

Question

hi i have a problem
i had a query
select distint s_date
from syadm.sauda
where s_cust is null and s_city ='z' and s_date between :a1 and :a2 order by s_date;
the platform i am using is centura sql windiows now i want to execite this same query in oracle if i am executuing the same query its taking lot of time but in sql talk it is fast.....
if i give the binding variables...the execution from the back end is fast(in direct oracle).. if i am running through the application it taking lot of time ....
can u tell me why...?
i had changed made3 a small changes in my application
S_DATE BETWEEN ' " || SalFmtFormatDateTime( dfFrom, 'dd-MMM-yyyy' ) || "' AND '" || SalFmtFormatDateTime( dfTo, 'dd-MMM-yyyy' ) ||"'"
after changing it its fast .but i dont feel that this is the appropriate reason for it......

Answer 1

You most likely have
i. s_date defined as a DATE column
ii. bind variables "a1" and "a2" being passed as Character fields.
Oracle wouldn't be using the DATE Index on s_date if the predicates are Character, although it can do Implicit Conversion to filter rows as it fetches them in a FullTableScan.
If i. and ii. are the case, you could change
and s_date between :a1 and :a2to
and s_date between to_date(:a1,'DD-MON-YYYY') and to_date(:a2,'DD-MON-YYYY')If you need to filter for Hours:Minutes:Seconds as well, you can include them in the DateMask of the to_date function.