IF  條件1 THEN
   執(zhí)行的邏輯1;
ELSIF 條件2 THEN  --條件1不滿足的時(shí)候，會先判斷是否滿足條件2
   執(zhí)行的邏輯2;
ELSE   ---條件1 和條件2 都不滿足
   執(zhí)行的邏輯3;
END IF;  ---結(jié)束 IF ELSE 條件判斷

select * from emp where empno=7788;

DECLARE
  v_EMPNO number := &input;
  v_SAL   number;
BEGIN
  select sal into v_SAL from emp where empno = v_EMPNO;
  IF v_SAL < 1000 THEN
    UPDATE emp set comm = nvl(comm, 0) + 300 where empno = v_EMPNO;
  -- commit;
  ELSIF v_SAL between 1000 and 2000 THEN
    --條件1不滿足的時(shí)候，會先判斷是否滿足條件2
    UPDATE emp set comm = nvl(comm, 0) + 200 where empno = v_EMPNO;
  -- commit;
  ELSE
    ---條件1 和條件2 都不滿足
    UPDATE emp set comm = nvl(comm, 0) + 100 where empno = v_EMPNO;
  END IF; ---結(jié)束 IF ELSE 條件判斷
  -- commit;
END;

select * from emp where empno=7788;

DECLARE
  v_EMPNO EMP.EMPNO%TYPE := &input;
  v_COUNT number;
BEGIN
  select count(1)
    into v_COUNT
    from emp
   WHERE DEPTNO IN (SELECT DEPTNO FROM EMP WHERE EMPNO = V_EMPNO);
  IF v_COUNT < 3 THEN
    NULL;
  ELSIF v_COUNT >= 3 and v_COUNT < 5 THEN
    UPDATE emp
       set sal = sal - 100
     where DEPTNO IN (SELECT DEPTNO FROM EMP WHERE EMPNO = V_EMPNO);
    -- commit;
  ELSE
    UPDATE emp
       set sal = sal - 200
     where DEPTNO IN (SELECT DEPTNO FROM EMP WHERE EMPNO = V_EMPNO);
  END IF;
  -- commit;
END;