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How to increase varchar size of an existing column in a database without breaking existing data in MySQL?
Increase the varchar size of an existing column in a database with the help of CHANGE command. The syntax is as follows −
alter table yourTableName change yourColumnName yourColumnName dataType;
Here, we are creating a table with a single column and varchar size 200 −
mysql> create table IncreaseVarcharDemo −> ( −> StudentId varchar(200) −> ); Query OK, 0 rows affected (0.60 sec)
Now insert record in the table. The query is as follows −
mysql> insert into IncreaseVarcharDemo values('John123');
Query OK, 1 row affected (0.16 sec)Displaying all records from the table with the help of the following query −
mysql> select *from IncreaseVarcharDemo;
The following is the output −
+-----------+ | StudentId | +-----------+ | John123 | +-----------+ 1 row in set (0.00 sec)
The following is the query to increase varchar size from 200 to 1000 −
mysql> alter table IncreaseVarcharDemo change StudentId StudentId varchar(1000); Query OK, 0 rows affected (0.18 sec) Records: 0 Duplicates: 0 Warnings: 0
Now you can check the varchar size has been increased or not. The query is as follows −
mysql> desc IncreaseVarcharDemo;
The following is the output −
+-----------+---------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-----------+---------------+------+-----+---------+-------+ | StudentId | varchar(1000) | YES | | NULL | | +-----------+---------------+------+-----+---------+-------+ 1 row in set (0.03 sec)
Updated on: 30-Jul-2019
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