mysql - 如何改变sql上select语句的结果

Question

SELECT        tbl_varsity_2.idnumber AS IDNUMBER, CONCAT(tbl_varsity_2.firstname, ' ', tbl_varsity_2.middlename, '. ', tbl_varsity_2.lastname) AS NAME, 
                         COALESCE(tbl_attendance_2.login, { d '0000-00-00 00:00:00' }) AS LOGIN, COALESCE(tbl_attendance_2.logout, { d '0000-00-00 00:00:00' }) AS LOGOUT, 
                         tbl_attendance_2.totaltime AS TOTALTIME, tbl_varsity_2.sport AS SPORT FROM            tbl_varsity tbl_varsity_2 LEFT JOIN
                         tbl_attendance tbl_attendance_2 ON tbl_varsity_2.idnumber = tbl_attendance_2.idnumber WHERE (tbl_varsity_2.status = 'active') AND(tbl_varsity_2.idnumber != ALL (SELECT tbl_varsity_5.idnumber FROM tbl_varsity tbl_varsity_5  INNER JOIN tbl_attendance tbl_attendance_5 ON tbl_varsity_5.idnumber=tbl_attendance_5.idnumber WHERE (tbl_attendance_5.login BETWEEN '2012-11-23 00:00:00' AND '2012-11-25 00:00:00') AND (tbl_varsity_5.status='active')))

结果是 10169060 Shee-Ann G. Dela Cruz 2012-11-27 09:07:53 2012-11-27 14:08:03 <我想将此值更改为 [0000-00 -00 00:00:00]> 乒乓球女子 123456 Kevin S. Juanico 0000-00-00 00:00:00 0000-00-00 00:00:00 羽毛球男子12692070 Charie May C. Cudiamat 0000-00-00 00:00:00 0000-00-00 00:00:00 女篮

所以所有的值都是 0000-00-00 00:00:00

请帮忙

Answer 1

如果您希望在所有记录上显示 0000-00-00 00:00:00 值(因为您没有指定任何条件)，只需在您的选择语句中使用它:

SELECT tbl_varsity_2.idnumber AS IDNUMBER
    , CONCAT(tbl_varsity_2.firstname, ' ', tbl_varsity_2.middlename, '. ', tbl_varsity_2.lastname) AS NAME
    /*, COALESCE(tbl_attendance_2.login, { d '0000-00-00 00:00:00' }) AS LOGIN
    , COALESCE(tbl_attendance_2.logout, { d '0000-00-00 00:00:00' }) AS LOGOUT*/
    , '0000-00-00 00:00:00' AS LOGIN
    , '0000-00-00 00:00:00' AS LOGOUT
    , tbl_attendance_2.totaltime AS TOTALTIME
    , tbl_varsity_2.sport AS SPORT 
    FROM tbl_varsity tbl_varsity_2 
    LEFT JOIN tbl_attendance tbl_attendance_2 ON tbl_varsity_2.idnumber = tbl_attendance_2.idnumber 
    WHERE (tbl_varsity_2.status = 'active') 
        AND (tbl_varsity_2.idnumber != ALL (
                SELECT tbl_varsity_5.idnumber 
                    FROM tbl_varsity tbl_varsity_5  
                    INNER JOIN tbl_attendance tbl_attendance_5 ON tbl_varsity_5.idnumber=tbl_attendance_5.idnumber 
                    WHERE (tbl_attendance_5.login BETWEEN '2012-11-23 00:00:00' AND '2012-11-25 00:00:00') 
                        AND (tbl_varsity_5.status='active')
                )
            )