mysql - mysql 查询在某些天不能按名称分组

Question

我有一个 mysql 查询，我想按名称分组几天。现在，它只是按名称分组了一天，我不知道问题出在哪里，请您帮忙。

SELECT attendance.username,
       attendance.date,
       attendance.time_in,
       attendance.time_out,
       attendance_count.count_time,
       attendance_count.appendix
FROM attendance
LEFT JOIN attendance_count
    ON (attendance.date=attendance_count.date)
        AND (attendance.username = attendance_count.username)
WHERE (STR_TO_DATE(attendance.date, '%m/%d/%Y')
    BETWEEN STR_TO_DATE('01/21/2013', '%m/%d/%Y')
        AND STR_TO_DATE('02/20/2013', '%m/%d/%Y'))
GROUP BY attendance.username

Answer 1

“几天”是无法理解的。请提供有关它的更多信息。

SELECT attendance.username,
       attendance.date,
       attendance.time_in,
       attendance.time_out,
       attendance_count.count_time,
       attendance_count.appendix
FROM attendance
LEFT JOIN attendance_count
    ON (attendance.date=attendance_count.date)
    AND (attendance.username = attendance_count.username)
WHERE (STR_TO_DATE(attendance.date, '%m/%d/%Y')
    BETWEEN STR_TO_DATE('01/21/2013', '%m/%d/%Y')
    AND STR_TO_DATE('02/20/2013', '%m/%d/%Y'))
GROUP BY attendance.username , DAY(attendance.date)