hive查询，使用where子查询没有返回结果

Question

问题遇到的现象和发生背景

测试where语句，第二种语句返回0行数据

问题相关代码，请勿粘贴截图

```sql
select e.* from
(select name, salary, deductions["Federal Taxes"] as ded,
  salary * (1 - deductions["Federal Taxes"]) as salary_minus_fed_taxes from employees) e
where round(e.salary_minus_fed_taxes) > 70000;
------------------------结果-------------------------------
+------------+-----------+--------+---------------------------+
|   e.name   | e.salary  | e.ded  | e.salary_minus_fed_taxes  |
+------------+-----------+--------+---------------------------+
| John Doe   | 100000.0  | 0.2    | 80000.0                   |
| John Bob   | 300000.0  | 0.4    | 180000.0                  |
| John Bill  | 200000.0  | 0.3    | 140000.0                  |
+------------+-----------+--------+---------------------------+
----------------------------第二种方式：
select name, salary, deductions["Federal Taxes"] as ded,
  salary * (1 - deductions["Federal Taxes"]) as salary_minus_fed_taxes from employees
where (select salary * (1 - deductions["Federal Taxes"]) from  employees) = 80000.0;
----------------结果--------------------------------------
+-------+---------+------+-------------------------+
| name  | salary  | ded  | salary_minus_fed_taxes  |
+-------+---------+------+-------------------------+
+-------+---------+------+-------------------------+

Answer 1

where中又使用了一次emloyees表,和上面的emloyees表没有任何关联关系,你要根据80000.0来定位数据的话,应该是像下面这样写

select name, salary, deductions["Federal Taxes"] as ded,
  salary * (1 - deductions["Federal Taxes"]) as salary_minus_fed_taxes from employees
where   salary * (1 - deductions["Federal Taxes"])  = 80000.0;

当然我不确定你这个显示是否有小数位四舍五入,或许要改成

round(salary * (1 - deductions["Federal Taxes"]) ,1) = 80000.0