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);

Similar codes

5 votes278 views4 answers
Rollback to in sql
SQL
2 votes261 views1 answer
Alter table add multiple columns postgresql
SQL
0 vote268 views1 answer
Sql get guid
SQL
7 votes346 views2 answers
Drop index oracle
SQL
0 vote357 views1 answer
Php insert null mysql
SQL
0 vote287 views1 answer
Sql server list table sizes
SQL
1 vote283 views1 answer
Round function in sql oracle
SQL
56 votes503 views5 answers
Psql create user
SQL
0 vote257 views1 answer
Difference between cross apply and inner join
SQL
0 vote269 views2 answers
Sql server set default value equal to auto increment
SQL