On Thu, 28 Mar, 2019, 4:33 PM Steve Atkins, <steve@xxxxxxxxxxx> wrote:
> On Mar 28, 2019, at 8:29 AM, Ron <ronljohnsonjr@xxxxxxxxx> wrote:
>
> On 3/28/19 3:23 AM, Sameer Kumar wrote:
> [snip]
>> You can write a query with upper function:
>>
>> select * from emp where upper(ename)=upper('aaa');
>
> That's a guaranteed table scan.
Unless you have an index on upper(ename).
Yup, with this or overloading "=", one can create an _expression_ based index and benefit from it.
Cheers,
Steve
