These conditions won't work in Oracle as you intend
If v_FromDt = '' THEN
ELSIF v_ToDt = '' THEN
A zero-length string is NULL in oracle and you can't check for null with an equality.
Instead write them like this...
If v_FromDt IS NULL THEN
ELSIF v_ToDt IS NULL THEN
Also in Oracle, you don't put column names inside brackets.
If you must use mixed case columns and/or columns with spaces in the names, then put the names in double quotes
For example
Instead of [Bank Address] you would use "Bank Address"
If v_FromDt = '' THEN
ELSIF v_ToDt = '' THEN
A zero-length string is NULL in oracle and you can't check for null with an equality.
Instead write them like this...
If v_FromDt IS NULL THEN
ELSIF v_ToDt IS NULL THEN
Also in Oracle, you don't put column names inside brackets.
If you must use mixed case columns and/or columns with spaces in the names, then put the names in double quotes
For example
Instead of [Bank Address] you would use "Bank Address"
I'm not sure what you were trying to do here...
dbo.LON_RPT_fnDayOrderedCo
If you are using 12c, you can have procedures that return result sets, but that is not normal coding for Oracle