EN
PostgreSQL - count rows with NULL values
0 points
In this article, we would like to show you how to count rows with NULL values in PostgreSQL.
Quick solution:
xxxxxxxxxx1
SELECT COUNT(*) AS "alias_name"2
FROM "table_name"3
WHERE "column_name" IS NULL;To show you how to count rows with NULL values, we will use the following users table:
Note:
At the end of this article you can find database preparation SQL queries.
In this example, we will count the number of rows with NULL values in department_id column.
Query
xxxxxxxxxx1
SELECT COUNT(*) AS "NULL_values_in_column"2
FROM "users"3
WHERE "department_id" IS NULL;Result:
create_tables.sql file:
xxxxxxxxxx1
CREATE TABLE "users" (2
"id" SERIAL,3
"name" VARCHAR(50) NOT NULL,4
"surname" VARCHAR(50) NOT NULL,5
"department_id" INTEGER,6
"salary" DECIMAL(15,2) NOT NULL,7
PRIMARY KEY ("id")8
);insert_data.sql file:
xxxxxxxxxx1
INSERT INTO "users"2
( "name", "surname", "department_id", "salary")3
VALUES4
('John', 'Stewart', 1, '6000'),5
('Chris', 'Brown', 2, '6000'),6
('Kate', 'Lewis', 3, '4000'),7
('Ailisa', 'Gomez', NULL, '4000'),8
('Gwendolyn', 'James', NULL, '4000'),9
('Simon', 'Collins', 4, '4000'),10
('Taylor', 'Martin', 2, '2000'),11
('Andrew', 'Thompson', NULL, '2000');