如何在 CASE 中使用 BETWEEN

【问题标题】：how to using BETWEEN in CASE如何在 CASE 中使用 BETWEEN
【发布时间】：2021-12-20 01:09:36
【问题描述】：

所以我想提出一个案例，如果在接受年份和当前年份（sysdate）之间是 1 到 5，它将是 1 级和 6 到 10 级 2

我使用这样的代码

select first_name,
       case trunc(months_between(sysdate, hire_date) / 12)
         when between 1 and 5 then
          '1'
         when between 6 and 10 then
          '2'
         when between 11 and 15 then
          '3'
         else
          '4'
       end as information
  from employees;

但在 1 到 5 之间出现错误提示“缺少关键字”

在哪里 EMPLOYEES 表包含 EMPLOYEE_ID,FIRST_NAME,HIRE_DATE 列

【问题讨论】：

标签： sql oracle oracle11g

【解决方案1】：

因为表达式应该单独写在每个when子句之后，例如

select first_name,
       case 
         when trunc(months_between(sysdate, hire_date) / 12) between 1 and 5 then
          '1'
         when trunc(months_between(sysdate, hire_date) / 12) between 6 and 10 then
          '2'
         when trunc(months_between(sysdate, hire_date) / 12) between 11 and 15 then
          '3'
         else
          '4'
       end as information
  from employees;

或者更优雅的选择是

with emp(first_name,year_diff) as
(
 select first_name, trunc(months_between(sysdate, hire_date) / 12) from employees
)
select first_name,
       case 
         when year_diff between 1 and 5 then
          '1'
         when year_diff between 6 and 10 then
          '2'
         when year_diff between 11 and 15 then
          '3'
         else
          '4'
       end as information
  from emp;

【讨论】：