To verify the same, we will try to ADD the same column without checking the condition. No error is thrown by the MySQL server, which shows that the condition has been checked successfully before calling the ALTER TABLE statement. What if the column already exists in the table sale_details? Let us call the procedure addColumnToTable() again. Output in image_4 shows the new column sale_person_designation in the table is added. We will again execute the DESC sale_details statement to verify if the column got added or not.
Procedure addColumnToTable is created and called successfully. NOT EXISTS( (SELECT * FROM information_schema.COLUMNS WHERE TABLE_SCHEMA=DATABASE()ĪND COLUMN_NAME='sale_person_designation' AND TABLE_NAME='sale_details') )ĪLTER TABLE sale_details ADD sale_person_designation varchar(255) New_table_name – Use this new table name.DROP PROCEDURE IF EXISTS addColumnToTable $$ Table_name – This is the table that needs to be renamed. In MySQL, you can rename a table by using the following syntax: ALTER TABLE table_name RENAME TO new_table_name In MySQL, a column can be renamed by using the ALTER TABLE statement: ALTER TABLE table_name CHANGE COLUMN old_name new_name column_definition Example ALTER TABLE employees CHANGE COLUMN city city_name varchar ( 20 ) NOT NULL Here is an example of using the ALTER TABLE statement to remove a column from a MySQL table. Table_name – Modify the name of the table.Ĭolumn_name – Deletes the column from the table by its name. Using the ALTER TABLE statement in MySQL, you can drop a column in a table as follows: Syntax ALTER TABLE table_name DROP COLUMN column_name ALTER TABLE employees MODIFY last_name varchar(55) NULL AFTER first_name, MODIFY first_name varchar(30) NOT NULL Using the ALTER TABLE statement, we can modify multiple columns in a MySQL table. Using the ALTER TABLE statement, you can modify multiple columns in a table in MySQL: Syntax ALTER TABLE table_name MODIFY column_name column_definition, MODIFY column_name column_definition. This ALTER TABLE example will modify the column called last_name to be a data type of varchar(50) and force the column to allow NULL values. ALTER TABLE employees MODIFY COLUMN salary INT
MYSQL ADD COLUMN HOW TO
Here’s an example of how to use the ALTER TABLE statement to modify a column in a MySQL table.
Modifying a column in a MySQL table (using the ALTER TABLE statement) is as follows: ALTER TABLE table_name MODIFY column_name column_definition The country column will be created as a varchar(35) NULL column and will appear after the city column in the table. The city field will be created as a varchar(40) NOT NULL column and will appear after the last_name column in the table. In the ALTER TABLE example, the city and country columns are added to the employee table. ALTER TABLE employees ADD city varchar(40) NOT NULL AFTER last_name, ADD country varchar(35) NULL AFTER city Here is an example of how to add multiple columns to a MySQL table using the ALTER TABLE command. The following query can be used to add a column named “address” to the “employees” table: ALTER TABLE employeesĪdding multiple columns to a MySQL table (with the ALTER TABLE statement) requires the following syntax: ALTER TABLE table_name ADD new_column_name column_definition, ADD new_column_name column_definition.
By default, the new column will be added at the end of the table if this parameter is not specified. Specifies where the column should be created in the table. New_column_name – To add a new column to the table, give it a name.Ĭolumn_definition – Defining the datatype and definition of the column (NULL or NOT NULL, etc).įIRST | AFTER column_name – This is optional. Table_name – To modify, enter the table name. Add column in table SyntaxĪdding a column to a table in MySQL (using ALTER TABLE) is as follows: ALTER TABLE table_name ADD new_column_name column_definition It is also possible to rename a table with the ALTER TABLE statement in MySQL. Using the ALTER TABLE statement in MySQL, you can add, modify, or delete columns from a table.
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