SQL COUNT: 例

例
サンプルデータベース

#1

SELECT COUNT(*) FROM employees;

#2

SELECT COUNT(*) FROM employees WHERE department_id = 6;

#3

SELECT COUNT(*) FROM employees WHERE job_id = 9;

#4

SELECT department_id, COUNT(*) FROM employees GROUP BY department_id;

#5

SELECT e.department_id, department_name, COUNT(*) FROM employees e INNER JOIN departments d ON d.department_id = e.department_id GROUP BY e.department_id;

#6

SELECT e.department_id, department_name, COUNT(*) FROM employees e INNER JOIN departments d ON d.department_id = e.department_id GROUP BY e.department_id ORDER BY COUNT(*) DESC;

#7

SELECT e.department_id, department_name, COUNT(*) FROM employees e INNER JOIN departments d ON d.department_id = e.department_id GROUP BY e.department_id HAVING COUNT(*) > 5 ORDER BY COUNT(*) DESC;

#8

SELECT COUNT(job_id) FROM employees;

#9

SELECT COUNT(DISTINCT manager_id) FROM employees;

テーブルリスト

countries

SELECT * FROM countries;

departments

SELECT * FROM departments;

dependents

SELECT * FROM dependents;

employees

SELECT * FROM employees;

jobs

SELECT * FROM jobs;

locations

SELECT * FROM locations;

regions

SELECT * FROM regions;

SQLクエリ

実行

クリアフォーマット縮小

リロード

結果