เปรียบเทียบผลการ Query ระหว่างมีการใช้ HAVING และการใช้คำสั่งคำนวณลงใน WHERE

SELECT * FROM (
    SELECT 
        O.id,
        O.id AS contract_id,
        O.lot_no,
        O.job_id,
        O.contract_no,
        O.create_date AS date,
        FLOOR((UNIX_TIMESTAMP() - O.create_date) / 86400) AS diff,
        3 AS type,
        O.create_date_comment AS comment,
        O.create_date_alarm AS alarm
    FROM `cdms_db`.`app_contract` AS O 
    WHERE O.`department` IN (1) 
    HAVING `diff` >= 55 AND `diff` > O.`create_date_alarm`
) AS Z;

SELECT * FROM (
    SELECT 
        O.id,
        O.id AS contract_id,
        O.lot_no,
        O.job_id,
        O.contract_no,
        O.create_date AS date,
        FLOOR((UNIX_TIMESTAMP() - O.create_date) / 86400) AS diff,
        3 AS type,
        O.create_date_comment AS comment,
        O.create_date_alarm AS alarm
    FROM cdms_db.app_contract AS O 
    WHERE 
        O.department IN (1) 
        AND FLOOR((UNIX_TIMESTAMP() - O.create_date) / 86400) >= 55 
        AND FLOOR((UNIX_TIMESTAMP() - O.create_date) / 86400) > O.create_date_alarm
) AS Z;