In MySQL, there are two approaches by which you can reset the MySQL field to default value. One is default keyword and another is default() function.
Case 1: Using default keyword. The syntax is as follows:
UPDATE yourTableName SET yourColumnName=default where yourCondition;
Case 2: Using default() function. The syntax is as follows:
UPDATE yourTableName SET yourColumnName=default(yourColumnName) where yourCondition;
To understand the above syntax, let us create a table. The query to create a table is as follows:
mysql> create table Default_Demo -> ( -> Id int NOT NULL AUTO_INCREMENT, -> Name varchar(20), -> Age int, -> Salary float, -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.73 sec)
Insert some records in the table using insert command. The query is as follows:
mysql> insert into Default_Demo(Name,Age,Salary) values('John',23,405.56);
Query OK, 1 row affected (0.18 sec)
mysql> insert into Default_Demo(Name,Age,Salary) values('Carol',25,1000.98);
Query OK, 1 row affected (0.22 sec)
mysql> insert into Default_Demo(Name,Age,Salary) values('Larry',21,987.24);
Query OK, 1 row affected (0.09 sec)
mysql> insert into Default_Demo(Name,Age,Salary) values('Sam',24,986.10);
Query OK, 1 row affected (0.17 sec)
mysql> insert into Default_Demo(Name,Age,Salary) values('Mike',22,10000.50);
Query OK, 1 row affected (0.17 sec)
mysql> insert into Default_Demo(Name,Age,Salary) values('David',26,100.45);
Query OK, 1 row affected (0.20 sec)Display all records from the table using select statement. The query is as follows:
mysql> select *from Default_Demo;
The following is the output:
+----+-------+------+---------+ | Id | Name | Age | Salary | +----+-------+------+---------+ | 1 | John | 23 | 405.56 | | 2 | Carol | 25 | 1000.98 | | 3 | Larry | 21 | 987.24 | | 4 | Sam | 24 | 986.1 | | 5 | Mike | 22 | 10000.5 | | 6 | David | 26 | 100.45 | +----+-------+------+---------+ 6 rows in set (0.00 sec)
Here is the query to reset the MySQL field to default values.
Case 1: Using default keyword. The query is as follows:
mysql> update Default_Demo set Age=Default where Id=6; Query OK, 1 row affected (0.10 sec) Rows matched: 1 Changed: 1 Warnings: 0
Now you can check the table record, the column Age is NULL where Id is 6. The query is as follows:
mysql> select *from Default_Demo;
The following is the output:
+----+-------+------+---------+ | Id | Name | Age | Salary | +----+-------+------+---------+ | 1 | John | 23 | 405.56 | | 2 | Carol | 25 | 1000.98 | | 3 | Larry | 21 | 987.24 | | 4 | Sam | 24 | 986.1 | | 5 | Mike | 22 | 10000.5 | | 6 | David | NULL | 100.45 | +----+-------+------+---------+ 6 rows in set (0.00 sec)
Look at the Id 6 in which Age column has been updated with default value NULL.
Case 2: Now you can also use default() function. Here, update the Salary column with default value where Id is 6. The query is as follows:
mysql> update Default_Demo set Salary=Default(Salary) where Id=6; Query OK, 1 row affected (0.21 sec) Rows matched: 1 Changed: 1 Warnings: 0
Now check the table record where Id is 6.
mysql> select *from Default_Demo where Id=6;
The following is the output:
+----+-------+------+--------+ | Id | Name | Age | Salary | +----+-------+------+--------+ | 6 | David | NULL | NULL | +----+-------+------+--------+ 1 row in set (0.00 sec)
Look at the salary column the default value NULL is updated successfully.