Can I have a function within a SELECT query? - sql

Question

Can I have a function within select statement like this?
select
myseq.nextval,
getDoctor(dbNumber,C.code,DOCCODE),
getDoctor(dbNumber,C.code,RFDOCCODE),
...
from charges c
where type='R';
Here getdoctor points to a function that checks two tables and returns a value:
create or replace function getDoctor(dbNumber IN NUMBER,code IN VARCHAR2(10),doccode IN VARCHAR2(10), OUT DOCID VARCHAR2(10))
is
begin
DOCID:= nvl((select MDOCID from NEW_PROVIDERS NP where dbNumber=NP.dbNumber and code=NP.code and doccode=NP.doccode),
select MDOCID from ProvidersProxy P where P.originalDB=dbNumber and code=P.originalGroup and doccode=P.originalDocCode);
return DOCID;
end getDoctor;

Answer 1

Write this (don't forget about the "p_" prefixes):
create or replace function getDoctor(
p_dbNumber IN NUMBER,
p_code IN VARCHAR2(10),
p_doccode IN VARCHAR2(10)
) return varchar2
is
l_DOCID VARCHAR2(10);
begin
begin
select MDOCID
into l_DOCID
from NEW_PROVIDERS NP
where p_dbNumber=NP.dbNumber
and p_code=NP.code
and p_doccode=NP.doccode
;
exception
when no_data_found then
select MDOCID
into l_DOCID
from ProvidersProxy P
where P.originalDB=p_dbNumber
and p_cpcode=P.originalGroup
and p_doccode=P.originalDocCode
;
end;
return l_DOCID;
end getDoctor;

Answer 2

The basic signature for an Oracle SQL usable function (which is well documented everywhere), is of the form:
FUNCTION my_function (param1 datatype, param2 datatype)
RETURN datatype
IS
local_variable1 datatype;
local_variable2 datatype;
BEGIN
-- Do something awesome
return local_variable;
/* Optional Exceptions Block */
END;
So in your case (with some rewriting of the NVL()) then:
create or replace function getDoctor(p_dbNumber IN NUMBER, p_code IN VARCHAR2, p_doccode IN VARCHAR2)
return varchar2
is
DOCID VARCHAR2(10);
begin
select MDOCID into DOCID
from NEW_PROVIDERS NP
where p_dbNumber=NP.dbNumber
and p_code=NP.code
and p_doccode=NP.doccode;
return DOCID;
EXCEPTION
when no_data_found then
select MDOCID INTO DOCID
from ProvidersProxy P
where P.originalDB=p_dbNumber
and p_code=P.originalGroup
and p_doccode=P.originalDocCode;
return DOCID;
end getDoctor;