MySQL query to replace a column value

Let us first create a table −

mysql> create table DemoTable
(
   StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY,
   Score int
);
Query OK, 0 rows affected (0.45 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable(Score) values(56);
Query OK, 1 row affected (0.24 sec)
mysql> insert into DemoTable(Score) values(78);
Query OK, 1 row affected (0.09 sec)
mysql> insert into DemoTable(Score) values(34);
Query OK, 1 row affected (0.10 sec)
mysql> insert into DemoTable(Score) values(55);
Query OK, 1 row affected (0.37 sec)

Display all records from the table using select statement −

mysql> select *from DemoTable;

This will produce the following output −

+-----------+-------+
| StudentId | Score |
+-----------+-------+
|         1 |    56 |
|         2 |    78 |
|         3 |    34 |
|         4 |    55 |
+-----------+-------+
4 rows in set (0.00 sec)

Following is the query to replace column value −

mysql> update DemoTable
   set Score=95 where StudentId=3;
Query OK, 1 row affected (0.12 sec)
Rows matched : 1 Changed : 1 Warnings : 0

Let us check the table records once again −

mysql> select *from DemoTable;

This will produce the following output −

+-----------+-------+
| StudentId | Score |
+-----------+-------+
|         1 |    56 |
|         2 |    78 |
|         3 |    95 |
|         4 |    55 |
+-----------+-------+
4 rows in set (0.00 sec)