Αποτελέσματα Αναζήτησης
Indexes of two types can be added: when you define a primary key, MySQL will take it as index by default. Explanation. Primary key as index. Consider you have a tbl_student table and you want student_id as primary key: ALTER TABLE `tbl_student` ADD PRIMARY KEY (`student_id`)
ALTER TABLE upgrades MySQL 5.5 temporal columns to 5.6 format for ADD COLUMN, CHANGE COLUMN, MODIFY COLUMN, ADD INDEX, and FORCE operations.
ALTER TABLE t2 ADD d TIMESTAMP; 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);
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
20 Απρ 2024 · MySQL ALTER TABLE ADD and DROP column, INDEX, PRIMARY KEY and FOREIGN KEY. Here is the structure and index of tstpurch and torder table.
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.
Besides the CREATE INDEX statement, you can use the ALTER TABLE statement to add a functional index to a table: ALTER TABLE table_name ADD INDEX index_name((fn)); Code language: SQL (Structured Query Language) (sql) MySQL functional index example. We’ll use the orders table from the sample database:
