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

2 votes356 views1 answer
Scaffold npgsql net core
SQL
1 vote316 views1 answer
Full text index mysql
SQL
0 vote362 views1 answer
Clear query cache sql server
SQL
0 vote349 views1 answer
Firebird where
SQL
-1 vote322 views2 answers
Sql server date format yyyy-MM-ddThh:mm:ss
SQL
0 vote335 views1 answer
Ora 00001 error catch plsql
SQL
5 votes350 views1 answer
Sort order on two columns sql
SQL
37 votes348 views3 answers
Postgresql insert column
SQL
0 vote382 views2 answers
Execute stored procedure without db set
SQL
3 votes349 views2 answers
Get current year sql
SQL