我有两个表,一个用于用户,另一个用于出席。我需要在特定日期显示不在考勤表上的用户。
这是我的表格:
USER_TABLE
| ID | Name |
-------------------
| 1 | John |
| 2 | Peter |
| 3 | Anne |
| 4 | May |
ATTENDANCE_TABLE
| ID | Date |
--------------------------------
| 2 | 2019-02-16 |
| 2 | 2019-02-17 |
| 2 | 2019-02-18 |
| 3 | 2019-02-17 |
| 4 | 2019-02-18 |
我需要选择“2019-02-18”中不存在的所有用户。
所以结果应该是这样的。
| ID | Name |
-------------------
| 1 | John |
| 3 | Anne |
谢谢。
试试这个查询,
select ID, Name
from USER_TABLE UT
where ID not in (select ID from ATTENDANCE_TABLE where date = '2019-02-18')
select ID, Name
from USER_TABLE UT
where ID not in (select ID from ATTENDANCE_TABLE where date = '2019-02-18')
Drop table if exists my_users;
Create table my_users
(User_ID serial primary key
,Name varchar(100) not null unique
);
Insert into my_users values
(1,'John'),
(2,'Peter'),
(3,'Anne'),
(4,'May');
Drop table if exists my_ATTENDANCE;
Create table my_attendance
(user_ID INT NOT NULL
,Date date not null
,primary key(user_id,date)
);
Insert into my_attendance values
( 2 ,'2019-02-16'),
( 2 ,'2019-02-17'),
(2 ,'2019-02-18'),
(3 ,'2019-02-17'),
(4 ,'2019-02-18');
Select u.*
From my_users u
Left
Join my_attendance a
On a.user_id = u.user_id
and a.date = '2019-02-18'
Where a.user_id is null;
User_ID Name
3 Anne
1 John
您可以尝试使用左连接
SELECT a.id,name
FROM USER_TABLE a
LEFT JOIN ATTENDANCE_TABLE b ON a.id=b.id
AND b.date='2019-02-18'
AND b.id IS NULL
Select UserTable.Id, name
From UserTable left join AttendanceTable
On UserTable.Id=AttendanceTable.Id
Where date! =#2019-02-18#