Answers for "unique key mysql"

SQL
3

mysql set field unique

ALTER TABLE mytbl ADD UNIQUE (columnName);
Posted by: Guest on March-06-2020
0

sql unique

This constraint ensures all values in a column are unique.
Example 1 (MySQL): Adds a unique constraint to the id column when
creating a new users table.
CREATE TABLE users (
id int NOT NULL,
name varchar(255) NOT NULL,
UNIQUE (id)
);
Example 2 (MySQL): Alters an existing column to add a UNIQUE
constraint.
ALTER TABLE users
ADD UNIQUE (id);
Posted by: Guest on January-07-2021

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