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

1 vote138 views1 answer
Stop mysql server mac
SQL
4 votes185 views1 answer
Alter session set nls_date_format
SQL
0 vote266 views1 answer
How to use select union and loop
SQL
24 votes175 views4 answers
Delete db postgres
SQL
0 vote153 views1 answer
Mysql locate
SQL
3 votes188 views2 answers
Wp do sql query from function
SQL
0 vote176 views1 answer
How to add a Try/Catch to SQL Stored Procedure
SQL
4 votes204 views1 answer
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.s
SQL
0 vote152 views2 answers
Disallowed function mysql to_date()
SQL
0 vote94 views1 answer
FindAllBy
SQL