Search results
The ALTER TABLE statement is used to add, delete, or modify columns in an existing table. The ALTER TABLE statement is also used to add and drop various constraints on an existing table. ALTER TABLE - ADD Column. To add a column in a table, use the following syntax: ALTER TABLE table_name. ADD column_name datatype;
You will learn how to use the MySQL ALTER TABLE statement to add a column, alter a column, rename a column, drop a column and rename a table.
To add an index on column d and a UNIQUE index on column a: ALTER TABLE t2 ADD INDEX (d), ADD UNIQUE (a); To remove column c: ALTER TABLE t2 DROP COLUMN c; To add a new AUTO_INCREMENT integer column named c: ALTER TABLE t2 ADD c INT UNSIGNED NOT NULL AUTO_INCREMENT, ADD PRIMARY KEY (c); We indexed c (as a PRIMARY.
MySQL ALTER TABLE statement allows us to change the name of an existing table and the name of an existing column. It also provides the capability to add a new column and delete an existing column. The ALTER TABLE statement is always used with some other commands like ADD, DROP and modify according to the need.
ALTER TABLE changes the structure of a table. For example, you can add or delete columns, create or destroy indexes, change the type of existing columns, or rename columns or the table itself. You can also change characteristics such as the storage engine used for the table or the table comment.
With the ALTER TABLE statement, you can rename tables, rename columns, add columns, drop columns, modify column properties, etc. ALTER TABLE syntax. ALTER TABLE table_name [alter_action options], ... The alter_action is a modification action, and it may be: The ADD keyword can be used to add columns, indexes, constraints, etc., including:
17 lip 2024 · The drop command is used to delete databases from MySQL server or objects within a database. The rename command is used to change the name of a table to a new table name. In this MySQL Tutorial, we will learn Alter, Drop, Rename, Change Keyword, Modify Keyword, After keyword commands.
