Sql unique

Sql unique select

SELECT DISTINCT col1, col2, ....
FROM table_name;

SELECT col1, MIN(col2)
FROM table_name
GROUP BY col1;

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);

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