【PL/SQL练习】函数

1、必须返回一个值
2、只能在表达式调用

SQL> create or replace function fun1
  2   return number
  3  is
  4    v_sum_sal emp.sal%type;
  5
  6   begin
  7     select sum(sal) into v_sum_sal from emp where deptno=10;
  8     return v_sum_sal;
  9   end;
 10  /
Function created

SQL>
SQL> declare

  4    v_sumsal emp.sal%type;
  5
  6  begin
  7
  8     v_sumsal := fun1;
  9     dbms_output.put_line(v_sumsal);
 10
 11  end;

带有参数的函数：

IN：

SQL> create or replace function fun1
  2  ( v_deptno in number)
  3   return number
  4  is
  5    v_sum_sal emp.sal%type;
  6
  7   begin
  8     select sum(sal) into v_sum_sal from emp where deptno=v_deptno;
  9     return v_sum_sal;
 10   end;

SQL> declare
  2    v_sumsal emp.sal%type;
  3
  4  begin
  5
  6     v_sumsal := fun1(10);
  7     dbms_output.put_line(v_sumsal);
  8
  9  end;

OUT:

SQL> create or replace function fun2
  2
  3   (v_empno number , v_ename out varchar2,v_sal out number)
  4
  5   return number
  6
  7   is
  8
  9   begin
 10
 11     select ename,sal into v_ename,v_sal from emp where empno=v_empno;
 12     return v_sal;
 13   end;
 14  /
Function created

SQL> declare
  2
  3     v_salary emp.sal%type;
  4     v_ename emp.ename%type;
  5     v_sal emp.sal%type;
  6
  7   begin
  8       v_salary := fun2(7369,v_ename,v_sal);
  9       dbms_output.put_line ('Salary is: '||v_salary);
 10
 11   end;