MySQL聚合选择查询返回不正确的数据答案

【问题标题】：MySQL aggregate select query returning incorrect dataMySQL聚合选择查询返回不正确的数据
【发布时间】：2020-05-31 06:38:04
【问题描述】：

我有以下代码：

SELECT gl.account_description AS invoice_total, COUNT(ili.invoice_id) AS total_invoice, 
    SUM(ili.line_item_amount) AS total_convert
FROM general_ledger_accounts gl JOIN
     invoice_line_items ili 
     ON gl.account_number = ili.account_number JOIN
     invoices i
     ON ili.invoice_id = i.invoice_id
GROUP BY gl.account_description, i.invoice_date, ili.account_number
HAVING i.invoice_date BETWEEN '2014-04-01' AND '2014-06-30' AND
      COUNT(ili.account_number) > 1
ORDER BY account_description DESC;

在我的查询中，我应该返回 10 行数据，而我只有 7 行返回，而且没有一个包含正确的信息。我应该返回的是 general_ledger_accounts 表中的 account_description 列，invoice_line_items 表中的项目计数，invoice_line_items 表中具有相同帐号的 line_item_amount 列的总和。它应该只在日期“2014-04-01”和“2014-06-30”之间的发票中搜索。我应该加入发票表。

谁能看出我在语法上做错了什么来得到错误的结果？

【问题讨论】：

标签： mysql sql select aggregate-functions

【解决方案1】：

显然，您需要 WHERE 子句而不是 HAVING 子句来过滤日期 - 并从 GROUP BY 中删除日期（您没有选择它）：

SELECT gl.account_description AS invoice_total,
       COUNT(*) AS total_invoice, 
       SUM(ili.line_item_amount) AS total_convert
FROM general_ledger_accounts gl JOIN
     invoice_line_items ili 
     ON gl.account_number = ili.account_number JOIN
     invoices i
     ON ili.invoice_id = i.invoice_id
WHERE i.invoice_date BETWEEN '2014-04-01' AND '2014-06-30'
GROUP BY gl.account_description, ili.account_number
HAVING COUNT(*) > 1
ORDER BY account_description DESC;

不知道还有没有其他问题。

【讨论】：

【解决方案2】：

我怀疑您想从group by 子句中删除列i.invoice_date 和ili.account_number。否则，这三列的每个不同值都会得到一条记录，这似乎不是您想要的。

因此，您应该将日期上的过滤器移至where 子句：

SELECT 
    gl.account_description AS invoice_total, 
    COUNT(ili.invoice_id) AS total_invoice, 
    SUM(ili.line_item_amount) AS total_convert
FROM general_ledger_accounts gl 
INNER JOIN invoice_line_items ili 
    ON gl.account_number = ili.account_number 
INNER JOIN invoices i 
    ON ili.invoice_id = i.invoice_id
WHERE 
    i.invoice_date >= '2014-04-01' 
    AND i.invoice_date < '2014-07-01'
GROUP BY gl.account_description
HAVING COUNT(ili.account_number) > 1
ORDER BY g1.account_description DESC;

请注意，我将日期的条件修改为使用半开间隔：这样，您不必担心上个月是 30 天还是 31 天（或 28 或 29...）；如果有的话，这也可以顺利处理日期的时间部分。

【讨论】：