To add more than 1 column with ALTER table command, you can use MODIFY column command. The syntax is as follows −
alter table yourTableName modify column yourColumnName1 dataType, modify column yourColumnName2 dataType, . . . modify column yourColumnNameN dataType
To understand the above syntax, let us create a table. The following is the query −
mysql> create table AddColumn −> ( −> StudentID int, −> StudentName varchar(200) −> ); Query OK, 0 rows affected (0.49 sec)
Above we have two columns in the table “AddColumn”. In this we will see how to modify more than one column datatype −
mysql> alter table AddColumn −> modify column StudentName varchar(300), −> modify column StudentId varchar(50); Query OK, 0 rows affected (1.95 sec) Records: 0 Duplicates: 0 Warnings: 0
Check whether the modified column added successfully in the table or not. The query is as follows −
mysql> desc AddColumn;
The following is the output −
+-------------+--------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------------+--------------+------+-----+---------+-------+ | StudentId | varchar(50) | YES | | NULL | | | StudentName | varchar(300) | YES | | NULL | | +-------------+--------------+------+-----+---------+-------+ 2 rows in set (0.00 sec)
Now look at the sample output, both column have been changed.