EN
PostgreSQL - SELECT DISTINCT statement
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In this article, we would like to show you how to use SELECT DISTINCT
statement in PostgreSQL.
Quick solution:
SELECT DISTINCT "column1", "column2", "columnN"
FROM "table_name";
Practical example
To show how the SELECT DISTINCT
statement works, we will use the following table:
Note:
At the end of this article you can find database preparation SQL queries.
Example
In this example, we will display unique countries from the users
table.
Query:
SELECT DISTINCT "country"
FROM "users";
Output:
Database preparation
create_tables.sql
file:
CREATE TABLE "users" (
"id" SERIAL PRIMARY KEY,
"name" VARCHAR(100) NOT NULL,
"country" VARCHAR(15) NOT NULL
);
insert_data.sql
file:
INSERT INTO "users"
("name", "country")
VALUES
('Tom', 'Poland'),
('Chris', 'Belgium'),
('Jack', 'Belgium'),
('Kate', 'Algeria'),
('Denis', 'Germany'),
('Matt', 'Germany');