v9xJuUh7

1DROP TABLE IF EXISTS my_table;
2
3CREATE TABLE my_table 
4(id SERIAL PRIMARY KEY
5,user_id INT NOT NULL
6,dt DATETIME NOT NULL
7);
8
9INSERT INTO my_table (user_id,dt) VALUES (101,NOW());
10Query OK, 1 row affected (0.00 sec)
11
12SELECT * FROM my_table;
13+----+---------+---------------------+
14| id | user_id | dt                  |
15+----+---------+---------------------+
16|  1 |     101 | 2018-10-07 23:21:44 |
17+----+---------+---------------------+
181 row in set (0.00 sec)
19	
20INSERT INTO my_table (user_id,dt) 
21SELECT 101,NOW() 
22  FROM (SELECT 1) x 
23  LEFT 
24  JOIN my_table y 
25    ON y.user_id = 101 
26   AND y.dt >= NOW() - INTERVAL 60 SECOND 
27 WHERE y.id IS NULL;
28Query OK, 1 row affected (0.00 sec)
29Records: 1  Duplicates: 0  Warnings: 0
30
31SELECT * FROM my_table;
32+----+---------+---------------------+
33| id | user_id | dt                  |
34+----+---------+---------------------+
35|  1 |     101 | 2018-10-07 23:21:44 |
36|  2 |     101 | 2018-10-07 23:23:39 |
37+----+---------+---------------------+
382 rows in set (0.00 sec)
39	
40INSERT INTO my_table (user_id,dt) 
41SELECT 101,NOW() 
42  FROM (SELECT 1) x 
43  LEFT 
44  JOIN my_table y 
45    ON y.user_id = 101 
46   AND y.dt >= NOW() - INTERVAL 60 SECOND 
47 WHERE y.id IS NULL;
48Query OK, 0 rows affected (0.00 sec)
49
50SELECT * FROM my_table;
51+----+---------+---------------------+
52| id | user_id | dt                  |
53+----+---------+---------------------+
54|  1 |     101 | 2018-10-07 23:21:44 |
55|  2 |     101 | 2018-10-07 23:23:39 |
56+----+---------+---------------------+
572 rows in set (0.00 sec)