Oracle function to replace all names to their nick names? - sql

Question

I have a table called nicknames
Names nickname
vikram vik
James Jim
Robert Bob
Charles Dick
Richard Dick
Rich Dick
Want to create an Oracle function to replace names with their nicknames from the table in an input string
func_nicknames('vikram, James, Rajesh, Robert') should return the value 'vik, Jim, Rajesh, Bob'
CREATE OR REPLACE FUNCTION func_nicknames( in_val varchar2)
RETURN VARCHAR2
IS
O_VAL VARCHAR2(100) := in_val;
BEGIN
SELECT REPLACE(O_VAL,t.name,t.nickname) INTO O_VAL FROM nicknames t;
RETURN(O_VAL);
END func_nicknames;
The above code is throwing an error.
In SQL Server, the below code works fine:
CREATE OR ALTER FUNCTION getNicknames(#val NVARCHAR(MAX))
RETURNS NVARCHAR(MAX) AS
BEGIN
DECLARE #result NVARCHAR(MAX);
SET #result = #val;
SELECT #result = REPLACE(#result, name, nickname)
FROM nicknames;
RETURN #result;
END;
Similar code I want to create in Oracle.
Working code for oracle:
CREATE OR REPLACE FUNCTION getNicknames(in_val VARCHAR) RETURN VARCHAR IS
ret VARCHAR(2000);
v VARCHAR(2000);
CURSOR cur IS SELECT SRC_VAL_STR, TGT_VAL_STR FROM nicknames;
BEGIN
ret := in_val;
FOR x IN cur
LOOP
SELECT REPLACE(ret, x.name, x.nickname) INTO v FROM DUAL;
ret := v;
END LOOP;
RETURN ret;
END;

Answer 1

First you have to convert the parameter to a table, the rest is very straightforward:
create or replace function getNicknames (names varchar2) return varchar2 is
ret varchar2 (32000);
begin
with names (name) as (
select trim (column_value)
from xmlTable (('"'||replace (names, ',', '","')||'"')) x
)
select
listagg (coalesce (nickname, na.name), ', ') within group (order by null) into ret
from names na
left join nicknames ni on ni.name=na.name;
return ret;
end;
/
Execution and outcome:
exec dbms_output.put_line ('result='||getNicknames ('vikram, James, Rajesh, Robert'));
result=vik, Jim, Rajesh, Bob
On db<>fiddle.

Answer 2

Your SQL returns more than one row. It is an error.
Try this:
create or replace function f_nicks (pNames in varchar2)
return varchar2
is
tab dbms_utility.uncl_array;
nCntElements number := 0;
vEl varchar2(32000);
o_nicks varchar2(1000);
BEGIN
dbms_utility.comma_to_table(pNames, nCntElements, tab);
select listagg (nvl( n.nickname, t.listname), ',') nicks into o_nicks
from (select trim(column_value) listname, rownum lp
from table(tab) ) t , nicknames n where n.name (+) = t.listname ;
return o_nicks;
END;
--- Test function
select f_nicks ('James, vikram, James,James, Rajesh, Robert') from dual;
db fiddle