Unique in sql server

Sql unique rows

SELECT
DISTINCT country
FROM City;

Source: learnsql.com

Unique in sql server

CREATE TABLE Persons (
    ID int NOT NULL UNIQUE,
    LastName varchar(255) NOT NULL,
    FirstName varchar(255),
    Age int
);

How to select unique element in sql

DISTINCT
- select distinct * from employees; ==> 
  retrieves any row if it has at
  least a single unique column.

- select distinct first_name from employees; ==> 
      retrieves unique names
     from table. (removes duplicates)
     
- select distinct count(*) from employees;
     retrieve number of unique rows
     if any row has at least a single unique data.

Unique element in sql

DISTINCT
- select distinct * from employees; ==> retrieves any row if it has at
least a single unique column.
- select distinct first_name from employees; ==> retrieves unique names
from table. (removes duplicates)
- select distinct count(*) from employees; retrieve number of unique rows
if any row has at least a single unique data.

Sql unique select

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

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

Similar codes

0 vote375 views1 answer
Space not removing from column in sql
SQL
3 votes332 views1 answer
Postgres update column with value from another table
SQL
1 vote339 views2 answers
Install mysqldump ubuntu
SQL
1 vote358 views1 answer
Psql import backup file for windows
SQL
5 votes328 views2 answers
Sql create tabel with primary key auto_increment code
SQL
0 vote368 views1 answer
Postgresql list extensions
SQL
2 votes353 views1 answer
Mysql increment value by 1 in update
SQL
1 vote354 views1 answer
How to delay stored procedure execution in sql server
SQL
23 votes342 views3 answers
Mysqldump
SQL
2 votes354 views1 answer
Find all triggers in database
SQL