Question

有人可以解释一下我做错了什么吗？我完全是新手，我不知道该怎么做。

我试图显示1995年7月17日至1995年7月24日期间发出的Invoice：nr_invoice和发票金额，净值超过50，全部按日期排序。

SELECT INVOICE.NR_INVOICE, COUNT(COMMODITY.PRICE)
FROM INVOICE FULL JOIN LINE_INVOICE ON INVOICE.NR_INVOICE = LINE_INVOICE.FNR_INVOICE
 LEFT JOIN COMMODITY ON LINE_INVOICE.FID_TOWAR = COMMODITY.ID_COMMODITY
WHERE INVOICE.DATE_OF_ISSUE BETWEEN '1995-07-17' AND '1995-07-24'
  and COMMODITY.PRICE > 50
GROUP BY INVOICE.NR_INVOICE
ORDER BY INVOICE.DATE_OF_ISSUE

这是一个错误

专栏＆＃34; INVOICE.DATE_OF_ISSUE＆＃34;在ORDER BY子句中无效，因为它不包含在聚合函数或GROUP BY子句中。

Answer 1

没有理由为此查询使用外连接。无论如何，你的where条款正在将它们变成内连接。

要解决您的特定问题，您需要在DATE_OF_ISSUE中加入GROUP BY或使用汇总功能：

SELECT i.NR_INVOICE, COUNT(c.PRICE)
FROM INVOICE i JOIN
     LINE_INVOICE li
     ON i.NR_INVOICE = li.FNR_INVOICE JOIN
     COMMODITY c
     ON li.FID_TOWAR = c.ID_COMMODITY
WHERE i.DATE_OF_ISSUE BETWEEN '1995-07-17' AND '1995-07-24' AND
      c.PRICE > 50
GROUP BY i.NR_INVOICE, i.DATE_OF_ISSUE
ORDER BY i.DATE_OF_ISSUE;

编辑：

您的具体问题是：

我试图显示发票：nr_invoice和发票金额 1995年7月17日至1995年7月24日期间，净值更高超过50，全部按日期排序。

对此的查询将使用HAVING：

SELECT i.NR_INVOICE, SUM(c.PRICE)
FROM INVOICE i JOIN
     LINE_INVOICE li
     ON i.NR_INVOICE = li.FNR_INVOICE JOIN
     COMMODITY c
     ON li.FID_TOWAR = c.ID_COMMODITY
WHERE i.DATE_OF_ISSUE BETWEEN '1995-07-17' AND '1995-07-24' 
GROUP BY i.NR_INVOICE, i.DATE_OF_ISSUE
HAVING SUM(c.PRICE) > 50
ORDER BY i.DATE_OF_ISSUE;

注意：如果您在发票行中有数量值，则需要考虑该值。

Answer 2

您不能使用该列，因为它不在GROUPING中（如错误所述）。您可以按列的总和（根据您的需要的最小值或最大值）进行订购。像这样：

SELECT INVOICE.NR_INVOICE, COUNT(COMMODITY.PRICE)
FROM INVOICE FULL JOIN LINE_INVOICE ON INVOICE.NR_INVOICE = LINE_INVOICE.FNR_INVOICE
 LEFT JOIN COMMODITY ON LINE_INVOICE.FID_TOWAR = COMMODITY.ID_COMMODITY
WHERE INVOICE.DATE_OF_ISSUE BETWEEN '1995-07-17' AND '1995-07-24'
  and COMMODITY.PRICE > 50
GROUP BY INVOICE.NR_INVOICE
ORDER BY MIN(INVOICE.DATE_OF_ISSUE)

Answer 3

SELECT INVOICE.NR_INVOICE, COUNT(COMMODITY.PRICE)
FROM INVOICE FULL JOIN LINE_INVOICE ON INVOICE.NR_INVOICE = LINE_INVOICE.FNR_INVOICE
 LEFT JOIN COMMODITY ON LINE_INVOICE.FID_TOWAR = COMMODITY.ID_COMMODITY
WHERE INVOICE.DATE_OF_ISSUE BETWEEN '1995-07-17' AND '1995-07-24'
  and COMMODITY.PRICE > 50
GROUP BY INVOICE.NR_INVOICE
ORDER BY min(INVOICE.DATE_OF_ISSUE)

专栏＆＃34; INVOICE.DATE_OF_ISSUE＆＃34;在ORDER BY子句中无效，因为它不包含在聚合函数或GROUP BY子句中

3 个答案: