Oracle 使用For循环重写If-else块

如何使用for循环编写以下If-else块：

    BEGIN
        IF :new.plan_id = 1 THEN
          SELECT PLAN_MAX_START_HH24 INTO NEW_PLAN_MAX_START_HH24 FROM screening_plan WHERE plan_id = 1; 
          SELECT PLAN_MIN_START_HH24 INTO NEW_PLAN_MIN_START_HH24 FROM screening_plan WHERE plan_id = 1;
        ELSIF :new.plan_id = 2 THEN
          SELECT PLAN_MAX_START_HH24 INTO NEW_PLAN_MAX_START_HH24 FROM screening_plan WHERE plan_id = 2; 
          SELECT PLAN_MIN_START_HH24 INTO NEW_PLAN_MIN_START_HH24 FROM screening_plan WHERE plan_id = 2;
        ELSIF :new.plan_id = 3 THEN
          SELECT PLAN_MAX_START_HH24 INTO NEW_PLAN_MAX_START_HH24 FROM screening_plan WHERE plan_id = 3; 
          SELECT PLAN_MIN_START_HH24 INTO NEW_PLAN_MIN_START_HH24 FROM screening_plan WHERE plan_id = 3;
        ELSIF :new.plan_id = 4 THEN
          SELECT PLAN_MAX_START_HH24 INTO NEW_PLAN_MAX_START_HH24 FROM screening_plan WHERE plan_id = 4; 
          SELECT PLAN_MIN_START_HH24 INTO NEW_PLAN_MIN_START_HH24 FROM screening_plan WHERE plan_id = 4;
        END IF;
     END;

---

对于一些值为

1,2,3,4

的

plan\u id

，我必须选择

plan\u max\u start\u hh24

和

plan\u min\u start\u hh24

为什么您认为需要For循环？我假设plan_id是唯一的数字（即，上面的每个查询最多返回1行）

还有，为什么要做两个选择？您可以在一个select语句中将多个列返回到相应的变量中

我想你可能想要这样的东西：

  if :new.plan_id in (1, 2, 3, 4) then
    select plan_max_start_hh24, plan_min_start_hh24
    into   new_plan_max_start_hh24, new_plan_min_start_hh24
    from   screening_plan
    where  plan_id = :new.plan_id;
  end if;

---

不要忘记包含一个异常块，以考虑上面的查询不返回一行的情况（如果plan_id不是唯一的列，则返回多行）。

这正是我想要的。非常感谢。