Question

SELECT barcode, t3.employee,
SEC_TO_TIME(SUM(TIMESTAMPDIFF(SECOND, dateandtime, (SELECT IFNULL(MIN(dateandtime),NOW())
                                                  FROM wwtlog b
                                                 WHERE b.barcode = a.barcode
                                                   AND b.dateandtime  > a.dateandtime
                                                   AND b.inorout = 'IN'
                                                )))) timeused
FROM wwtlog a
    JOIN (SELECT t1.barcode, t1.employee FROM wwtlog t1
  JOIN (SELECT barcode, MAX(id) id FROM wwtlog GROUP BY barcode) t2
ON t1.id = t2.id AND t1.barcode = t2.barcode) t3 ON t1.barcode = barcode
WHERE inorout = 'OUT' and barcode IN (SELECT t1.barcode FROM wwtlog t1
                                JOIN (SELECT barcode, MAX(dateandtime) dateandtime FROM wwtlog GROUP BY barcode) t2
                                ON t1.barcode = t2.barcode AND t1.dateandtime = t2.dateandtime WHERE inorout = 'IN')
GROUP BY barcode;

任何有关这方面的帮助都会很棒，当我添加加入来获取t3.employee时，我开始得到这个。我有一种感觉，我不知道自己在做什么。

我试图获得唯一条形码，时间IN和时间OUT时间戳之间的总时间。我试图使用联接来获得最后一个项目（条形码）签出或签入的员工。如果你拿出t3.employee的加入，并且只是要求员工，它给了我第一个记录员工条形码，而不是最后一个。

Answer 1

您正在使用列条形码，但此列存在于多个表中，请尝试为每个条形码列分配表别名

SELECT a.barcode, t3.employee,
SEC_TO_TIME(SUM(TIMESTAMPDIFF(SECOND, dateandtime, (SELECT IFNULL(MIN(dateandtime),NOW())
                                                  FROM wwtlog b
                                                 WHERE b.barcode = a.barcode
                                                   AND b.dateandtime  > a.dateandtime
                                                   AND b.inorout = 'IN'
                                                )))) timeused
FROM wwtlog a
    JOIN (SELECT t1.barcode, t1.employee FROM wwtlog t1
  JOIN (SELECT barcode, MAX(id) id FROM wwtlog GROUP BY barcode) t2
ON t1.id = t2.id AND t1.barcode = t2.barcode) t3 ON t1.barcode = a.barcode
WHERE inorout = 'OUT' and a.barcode IN (SELECT t1.barcode FROM wwtlog t1
                                JOIN (SELECT barcode, MAX(dateandtime) dateandtime FROM wwtlog GROUP BY barcode) t2
                                ON t1.barcode = t2.barcode AND t1.dateandtime = t2.dateandtime WHERE inorout = 'IN')
GROUP BY a.barcode;

特别是在主表上，例如：wwtlog a

Answer 2

您在ON t1.barcode =条形码时缺少表格引用。由于条形码列在多个表中，因此需要严格识别，以免模糊不清。

字段列表中的“条形码”列不明确

2 个答案: