Using a pl sql variable in sql select value - select

Question

I'm having a function where I would like to get the info from the table based of the parameter.
p_text is something like 'name' , or 'email' or 'birthday' so in my cursist table that would be like calling the select cursist.name , cursist.email or cursist.birthday.
get_cursist_info(p_app => :APP_USER, p_text => 'name')
this is my function:
create or replace function get_cursist_info(p_app in varchar2, p_text in varchar2)
return varchar
is
v_userid varchar(200);
v_text varchar(200);
v_test varchar(200):= p_text;
begin
v_userid := get_cursist_id2(p_app);
select v_test
into v_text
from cursist
where cursist.cursistid = v_userid;
return v_text;
end get_cursist_info;
All it does now is getting the variabele v_test back (name) instead of the cursists name(Dave).
Isnt it possible to use a pl sql variable in the select? I don't really feel like making 8 functions for this.. :)

Answer 1

You can do this without dynamic sql which is less efficient by using CASE clause:
select CASE v_test
WHEN 'name' THEN name
WHEN 'email' THEN email
WHEN 'birthday' THEN birthday
ELSE null
END
into v_text
from cursist
where cursist.cursistid = v_userid;

Answer 2

You need to create your query dynamically:
create or replace function get_cursist_info(p_app in varchar2, p_text in varchar2)
return varchar
is
v_userid varchar2(200);
v_text varchar2(200);
v_test varchar2(200):= p_text;
v_sql varchar2(1000);
begin
v_userid := get_cursist_id2(p_app);
v_sql := 'select cursist.' || v_test || ' from cursist where cursist.cursistid = ' || v_userid;
execute immediate v_sql into v_text;
return v_text;
end get_cursist_info;
Hope that helps.