Add data to existing data in a MySQL Database?

You can use CONCAT() function for this. Let us first create a table −

mysql> create table DemoTable
   (
   UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY,
   UserName varchar(100)
   );
Query OK, 0 rows affected (0.43 sec)

Insert records in the table using insert command −

mysql> insert into DemoTable(UserName) values('John');
Query OK, 1 row affected (0.24 sec)
mysql> insert into DemoTable(UserName) values('Chris');
Query OK, 1 row affected (0.11 sec)
mysql> insert into DemoTable(UserName) values('Robert');
Query OK, 1 row affected (0.11 sec)

Display all records from the table using select statement −

mysql> select *from DemoTable;

This will produce the following output −

+--------+----------+
| UserId | UserName |
+--------+----------+
| 1      | John     |
| 2      | Chris    |
| 3      | Robert   |
+--------+----------+
3 rows in set (0.00 sec)

Here is the query to add data to existing data in MySQL database. The UserId 1 is concatenated with the name “Smith” to the already existed name−

mysql> update DemoTable
set UserName=concat(UserName,' Smith') where UserId=1;
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 −

+--------+------------+
| UserId | UserName   |
+--------+------------+
| 1      | John Smith |
| 2      | Chris      |
| 3      | Robert     |
+--------+------------+
3 rows in set (0.00 sec)