Примеры команд SQL в рамках урока #17

-- Соединение таблиц. INNER JOIN
-- https://www.youtube.com/watch?v=uTCr_nMmQjU

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-- Примеры команд SQL в рамках урока #17


SELECT * FROM EMPLOYEES
WHERE
    DEPARTMENT_ID IN
        (
            SELECT DEPARTMENT_ID
            FROM DEPARTMENTS
            WHERE DEPARTMENT_NAME IN ('IT', 'Finance')
        )
;

SELECT
    a.*
FROM
    EMPLOYEES a
    INNER JOIN DEPARTMENTS b ON a.DEPARTMENT_ID = b.DEPARTMENT_ID
WHERE
    b.DEPARTMENT_NAME IN ('IT', 'Finance')
;

SELECT
    a.*
FROM
    EMPLOYEES a
    INNER JOIN DEPARTMENTS b ON a.DEPARTMENT_ID = b.DEPARTMENT_ID
;

SELECT * FROM DEPARTMENTS_2
;

SELECT
    a.*
FROM
    EMPLOYEES a
    INNER JOIN DEPARTMENTS_2 b ON a.DEPARTMENT_ID = b.DEPARTMENT_ID
;

SELECT
    a.*, b.DEPARTMENT_NAME
FROM
    EMPLOYEES a
    INNER JOIN DEPARTMENTS_2 b ON a.DEPARTMENT_ID = b.DEPARTMENT_ID
;

SELECT
    a.*, b.DEPARTMENT_NAME
FROM
    EMPLOYEES a
    INNER JOIN DEPARTMENTS b ON a.DEPARTMENT_ID = b.DEPARTMENT_ID
WHERE
    b.DEPARTMENT_NAME IN ('IT', 'Finance')
;

SELECT
    a.EMPLOYEE_ID, a.FIRST_NAME, a.LAST_NAME, a.DEPARTMENT_ID, b.DEPARTMENT_NAME, b.LOCATION_ID
FROM
    EMPLOYEES a
    INNER JOIN DEPARTMENTS b ON a.DEPARTMENT_ID = b.DEPARTMENT_ID
WHERE
    b.DEPARTMENT_NAME IN ('IT', 'Finance')
;

SELECT
    b.EMPLOYEE_ID, b.FIRST_NAME, b.LAST_NAME, b.DEPARTMENT_ID, a.DEPARTMENT_NAME, a.LOCATION_ID
FROM
    DEPARTMENTS a
    INNER JOIN EMPLOYEES b ON a.DEPARTMENT_ID = b.DEPARTMENT_ID
WHERE
    a.DEPARTMENT_NAME IN ('IT', 'Finance')
;