In MySQL, how to automatically insert date and time while inserting NULL values ​​into other columns?

In MySQL, we can automatically insert the current date and time into this column when NULL values ​​are inserted into other columns by declaring the column as DEFAULT CURRENT_TIMESTAMP. In this case, we cannot declare the column in which we want to insert NULL value NOT NULL.

mysql> Create Table Testing1(Name Varchar(20),
RegStudent TIMESTAMP DEFAULT CURRENT_TIMESTAMP);
Query OK, 0 rows affected (0.15 sec)

The above query will create a table "Testing1" with one column named "Name" (not declared as "NOT NULL") and other columns named "RegDate" declared as DEFAULT CURRENT_TIMESTAMP. Now, when inserting a NULL value into the "name" column, the current date and time is automatically inserted into another column.

mysql> Insert into Testing1(Name) Values(NULL);
Query OK, 1 row affected (0.08 sec)

mysql> Insert into Testing1(Name) Values(NULL);
Query OK, 1 row affected (0.04 sec)

mysql> Select * from Testing1;
+------+---------------------+
| Name | RegStudent |
+------+---------------------+
| NULL | 2017-10-29 04:46:59 |
| NULL | 2017-10-29 04:47:02 |
+------+---------------------+
2 rows in set (0.05 sec)

From the above query, we can see that when inserting a NULL value in "Name", the date and time are also automatically inserted.

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