Hi Experts,
I'm facing a strange issue which I didn't face earlier. DB - Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
I've a table lets say "tab_1" & a column in that "col1". Column is of varchar2 datatype & can store nulls.
Let's say i run the query to get distinct values & their respective counts. Below is the output.
Now if i run:
select * from tab_1 where col1 !='A' -- Gets me incomplete resultset.
select * from tab_1 where nvl(col1,0) !='A' -- Gets me correct data.
So, my question is: Why am i not getting correct result in my 1st query? Why i need to put nvl for getting me correct stuff?
Pls. let me know if I need to brush my knowledge on null handlings & the way they're operated internally in oracle.
Or is there any component i have to ask my DBA to configure correctly.
TIA