To understand the concept, let us first create a demo table.
mysql> create table addToExistingValueDemo -> ( -> Instructor_Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> Instructor_Name varchar(30), -> Instructor_TechnicalSubject text -> ); Query OK, 0 rows affected (0.54 sec)
Insert some records in the table using insert command. The query is as follows −
mysql> insert into addToExistingValueDemo(Instructor_Name,Instructor_TechnicalSubject) values('John','C,C++'); Query OK, 1 row affected (0.15 sec) mysql> insert into addToExistingValueDemo(Instructor_Name,Instructor_TechnicalSubject) values('Carol','Java,Python'); Query OK, 1 row affected (0.18 sec) mysql> insert into addToExistingValueDemo(Instructor_Name,Instructor_TechnicalSubject) values('Bob','MySQL,SQL Server'); Query OK, 1 row affected (0.15 sec) mysql> insert into addToExistingValueDemo(Instructor_Name,Instructor_TechnicalSubject) values('David','DataStructure'); Query OK, 1 row affected (0.18 sec
Display all records from the table using select statement. The query is as follows −
mysql> select *from addToExistingValueDemo;
The following is the output
+---------------+-----------------+-----------------------------+ | Instructor_Id | Instructor_Name | Instructor_TechnicalSubject | +---------------+-----------------+-----------------------------+ | 1 | John | C,C++ | | 2 | Carol | Java,Python | | 3 | Bob | MySQL,SQL Server | | 4 | David | DataStructure | +---------------+-----------------+-----------------------------+ 4 rows in set (0.00 sec)
Here is the query to add to existing value in MySQL column using CONCAT function
mysql> update addToExistingValueDemo -> set Instructor_TechnicalSubject=concat(Instructor_TechnicalSubject,', Introduction To Algorithm') -> where Instructor_Id=4; Query OK, 1 row affected (0.10 sec) Rows matched: 1 Changed: 1 Warnings: 0
Let us check the table records once again to see the new changes. The query is as follows −
mysql> select *from addToExistingValueDemo;
The following is the output
+---------------+-----------------+------------------------------------------+ | Instructor_Id | Instructor_Name | Instructor_TechnicalSubject | +---------------+-----------------+------------------------------------------+ | 1 | John | C,C++ | | 2 | Carol | Java,Python | | 3 | Bob | MySQL,SQL Server | | 4 | David | DataStructure, Introduction To Algorithm | +---------------+-----------------+------------------------------------------+ 4 rows in set (0.00 sec)