EN
PostgreSQL - GROUP BY multiple columns
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In this article, we would like to show you how to use GROUP BY
statement with multiple columns in PostgreSQL.
Quick solution:
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SELECT "column1", "column2", "columnN"
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FROM "table_name"
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WHERE condition
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GROUP BY "column1", "column2", "columnN"
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ORDER BY "column_name";
To show how GROUP BY
with multiple columns works, we will use the following table:

Note:
At the end of this article you can find database preparation SQL queries.
In this example, we will display the number of users with the same name
and department_id
.
Query:
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SELECT "name", "department_id", COUNT(*)
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FROM "users"
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GROUP BY "name","department_id";
Result:

Result explanation:
As we see, the COUNT(*) column contains the number of users with the same name
and department_id
. For example, there are three people named Ailisa
in the department 3
.
create_tables.sql
file:
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CREATE TABLE "users" (
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"id" SERIAL,
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"name" VARCHAR(50) NOT NULL,
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"surname" VARCHAR(50) NOT NULL,
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"department_id" INTEGER,
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"salary" DECIMAL(15,2) NOT NULL,
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PRIMARY KEY ("id")
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);
insert_data.sql
file:
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INSERT INTO "users"
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( "name", "surname", "department_id", "salary")
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VALUES
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('John', 'Stewart', 1, '2000.00'),
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('Chris', 'Brown', 3, '2000.00'),
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('Chris', 'Lewis', 3, '2000.00'),
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('Kate', 'Lewis', 3, '2000.00'),
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('Kate', 'Stewart', 3, '2000.00'),
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('Ailisa', 'Lewis', 3, '2000.00'),
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('Ailisa', 'Gomez', 3, '3000.00'),
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('Gwendolyn', 'James', 2, '3000.00'),
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('Simon', 'James', 2, '2000.00'),
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('Simon', 'Brown', 3, '2000.00'),
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('Simon', 'Collins', 3, '3000.00');