Oracle 11g - 带有TimeStamp的Sql

Question

I have a table named Evrak and it has two columns which are Product_Date [timestamp(6)] and Evrak_Name[varchar2(50)]. There is a record which name is Evrak Test and Product_Date is
25-APR-12 12.00.00.000000000 PM.

When i want to run a query like ;

select * from Evrak Where Evrak.Product_Date  = TO_TIMESTAMP ('25.04.2012:00:00:00','DD.MM.YYYY:HH24:MI:SS')

It does return a null record, i' ve tried to change format type and have used to_date, to_char methods but did not managed to get the record. What am i missing here ? or is there any special usage while quering a timestamp column?

Answer 1

Try:

select * 
 from Evrak 
Where Evrak.Product_Date  = TO_TIMESTAMP ('25.04.2012:12:00:00','DD.MM.YYYY:HH24:MI:SS')

Since you want 25-APR-12 12.00.00.000000000 PM and not 25-APR-12 12.00.00.000000000 AM

Answer 2

Time stamps are finicky. Like floating point numbers, there may be insignificant bits that affect comparisons.

I would suggest returning things within a range. For instance, the following query returns time stamps within one second.

select *
from Evrak
Where abs(Evrak.Product_Date - TO_TIMESTAMP ('25.04.2012:00:00:00', 'DD.MM.YYYY:HH24:MI:SS')) < 1.0/(24*60*60)