[英]How group primary keys with different value but same name and using datediff
[英]How to perform UNION of the tables with same column name as their primary keys but different values
這是兩張表: 輸入:
Employees table:
+-------------+----------+
| employee_id | name |
+-------------+----------+
| 2 | Crew |
| 4 | Haven |
| 5 | Kristian |
+-------------+----------+
Salaries table:
+-------------+--------+
| employee_id | salary |
+-------------+--------+
| 5 | 76071 |
| 1 | 22517 |
| 4 | 63539 |
+-------------+--------+
我想要一個輸出,比如你如何執行加入但使用聯合。
聯合的輸出應如下所示:
employee_id | name | salary
2 crew. null
4. haven. 63539
5. Kristian 76071
1. null. 22517
並發布我想要執行選擇的工會,方法是選擇沒有姓名或沒有薪水的員工的employee_id
目前我正在處理的查詢:
select * from
(select employee_id, name, null as salary from employees
union all
select employee_id, null as name, salary from salaries)
as emp
where name is null or salary is null
結果如下所示:
{"headers": ["employee_id", "name", "salary"], "values": [[2, "Crew", null], [4, "Haven", null], [5, "Kristian" , null], [5, null, 76071], [1, null, 22517], [4, null, 63539]]}
如果使用此查詢:
select * from (selectemployee_id, name from employees union all selectemployee_id,salary from paid) as emp
結果如下所示:
{"headers": ["employee_id", "name"], "values": [[2, "Crew"], [4, "Haven"], [5, "Kristian"], [5, "76071" ], [1, "22517"], [4, "63539"]]}
這是一個完整的聯接:
Select coalesce(e.employeeid, s.employeeid) employed
e.name, e.salary
From employees e full join
Salaries s
On e.employeeid = s.employeeid
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.