Can we give multiple select statements in one function in PL/SQL

Question

Hi All,
I am new to the PL/SQL. Can you please help me with the following problem.
I am cretaing a function in which I have to extract some fields from three tables and to handle three tables I am first extracting the primary key from one table(acting as a foreign key for other table) in a variable declared in declare section, then I am selecting the required fields from the other table by giving that variable name in Where condition. My code is attached as well.
e.g
Create or Replace function <function name>(arguments)
Return return type
AS
a1 a%TYPE;
b_new b%TYPE;
n fn%TYPE
Select a into a1 from table1 where b like b_new;
Select fn into n from table2 where id like a1;
return a1,n; (can we pass record like this?)
end;

Answer 1

Left's first look at the approach you use.. 2 SQL statements that can be done using a single SQL statement.
Actually it is not as bad as some other code posted here where people go and write complex PL/SQL code to do what could have been done using a single SQL statement.
There are a couple of golden rules in Oracle development. One of these is to 'Maximise SQL and Minimise PL/SQL'.
Why take a value from one SQL statement into PL/SQL and then use that value in a second SQL statement?
Rather do this:
select
fn into n
from table2
where id like (Select a from table1 where b like b_new);Also keep in mind that in PL/SQL the above SQL construct is only able to fetch a single row - look at the bold above. The variable N can only hold a single value. If that SQL SELECT returns more than one value, how is variable N suppose to hold it?
I suggest that you read [url http://www.oracle.com/pls/db102/to_toc?pathname=appdev.102%2Fb14261%2Ftoc.htm&remark=portal+%28Books%29]Oracle® Database PL/SQL User's Guide and Reference guide.