Database advanced learning notes -- storage functions

--1. The difference between stored procedure and stored function
  Storage functions have return Return value
 
--2. The relationship between stored procedures and stored functions
Stored functions can be interchanged with stored procedures , The storage function can be called in stored procedure.
--3. Be careful
If there is only one return value , With storage functions , otherwise , Just use stored procedures .

--4. Storage function syntax
grammar ：create or replace function( Parameters Parameter type ) return Variable type is
begin
Code block ;
return Outcome variable ;
end;

example ; Create a function , Take employee number as parameter , Return the salary of the employee
create or replace function fun_name101(v_empno in emps.empno%type)
return emps.sal%type is
 v_sal emps.sal%type;
begin
select sal into v_sal from emps where empno=v_empno;
return v_sal;
end;

-- call
select fun_name101(7788) from dual;