連続した日付のコレクションを取得する

わかりました。基本的に、各LEFT JOINで、非常に簡単でした。 渡されたパラメータで開始日を除外する必要がありました。

また、休暇が承認されたかどうか、Approved_DateTimeでフィルタリングする必要がありました。 およびApproved_By 承認された場合に入力されたフィールド。また、期間の計算は、状況によっては少しずれていました。したがって、ストアドプロシージャは次のようになります。

DELIMITER $$

USE `test`$$

DROP PROCEDURE IF EXISTS `GetLeaveDates`$$

CREATE DEFINER=`root`@`%` PROCEDURE `GetLeaveDates`(pEmpID INT, pDateFrom DATETIME, pDateTo DATETIME, pApproved BOOLEAN)
BEGIN

SELECT 
    DATE_FORMAT(a.start_date,'%d/%m/%y') AS start,
CASE WHEN a.am_pm = 1 THEN "AM"
     WHEN a.am_pm = 2 THEN "PM"
     ELSE "" END AS start_am_pm,
    DATE_FORMAT(CASE WHEN pDateTo > MIN(c.start_date) THEN
        MIN(c.start_date)
    ELSE
        pDateTo
    END, '%d/%m/%y') AS end,
CASE WHEN c.am_pm = 1 THEN "AM"
     WHEN c.am_pm = 2 THEN "PM"
     ELSE "" END AS end_am_pm,
  CASE WHEN a.am_pm = 0 THEN
    CASE WHEN c.am_pm = 0 OR c.am_pm = 2 THEN
        DATEDIFF(MIN(c.start_date),a.start_date)+1
    WHEN c.am_pm = 1 THEN
        DATEDIFF(MIN(c.start_date),a.start_date)+0.5
    END
WHEN a.am_pm = 1 THEN
    CASE WHEN c.am_pm = 0 OR c.am_pm = 2 THEN
        DATEDIFF(MIN(c.start_date),a.start_date)+1
    WHEN c.am_pm = 1 THEN
        DATEDIFF(MIN(c.start_date),a.start_date)+0.5
    END
WHEN a.am_pm = 2 THEN
    CASE WHEN c.am_pm = 0 OR c.am_pm = 2 THEN
        DATEDIFF(MIN(c.start_date),a.start_date)+0.5
    WHEN c.am_pm = 1 THEN
        DATEDIFF(MIN(c.start_date),a.start_date)
    END 
END AS Duration

FROM t AS a
LEFT JOIN t AS b ON a.employee_id=b.employee_id AND a.start_date = ADDDATE(b.start_date,1) AND ISNULL(b.approved_datetime) <> pApproved AND b.start_date BETWEEN pDateFrom AND pDateTo
LEFT JOIN t AS c ON a.employee_id=c.employee_id AND a.start_date <= c.start_date AND ISNULL(c.approved_datetime) <> pApproved AND c.start_date BETWEEN pDateFrom AND pDateTo
LEFT JOIN t AS d ON c.employee_id=d.employee_id AND c.start_date = ADDDATE(d.start_date,-1) AND ISNULL(d.approved_datetime) <> pApproved AND d.start_date BETWEEN pDateFrom AND pDateTo
WHERE b.start_date IS NULL AND c.start_date IS NOT NULL AND d.start_date IS NULL
AND a.EMPLOYEE_ID = pEmpID
AND a.START_DATE BETWEEN pDateFrom AND pDateTo
AND ISNULL(a.approved_datetime) <> pApproved
AND a.start_date BETWEEN pDateFrom AND pDateTo
GROUP BY a.employee_id, a.start_date
; END$$

DELIMITER ;