在 Oracle SQL 中使用 DECODE 进行 GROUP BY (ORA-00979)

Question

我刚刚在 Whosebug 和其他网站上阅读了很多关于我的问题的已解决问题，但我仍然没有明白。我无法执行附加的代码，我收到 "ORA-00979" 错误，但我不明白为什么。我读到我不必在我的 GROUP BY 订单中列出 DECODE 或 COUNT 子句。我仍然得到错误。有谁知道为什么？

SELECT DISTINCT 
    company.company_id,   
    company.companyname_1,   
    customer.customer_id,   
    customer.customername_1,
    DECODE(receipt.table_name, 'PAYMENT', SUM(COUNT(receipt.receipt_id))) as inpayment
FROM 
            company
    JOIN customer ON company.company_id = customer.company_id
    JOIN debtor ON customer.customer_id = debtor.customer_id
    JOIN debtortrunk ON debtor.debtor_id = debtortrunk.debtor_id 
    JOIN receipt ON debtor.customer_id = receipt.customer_id AND debtor.deb_id = receipt.deb_id
WHERE
    receipt.created >= '24.01.2018' AND
    receipt.created <= '28.01.2018'
GROUP BY
    company.company_id,   
    company.companyname_1,   
    customer.customer_id,   
    customer.customername_1

Answer 1

您不能使用包含另一个聚合函数的聚合函数。

如果我没理解错你可以试试用条件聚合函数来做。

SELECT  
    company.company_id,   
    company.companyname_1,   
    customer.customer_id,   
    customer.customername_1,
    SUM(CASE WHEN receipt.table_name = 'PAYMENT' AND receipt.receipt_id IS NOT NULL THEN 1 ELSE 0 END) as inpayment
FROM 
            company
    JOIN customer ON company.company_id = customer.company_id
    JOIN debtor ON customer.customer_id = debtor.customer_id
    JOIN debtortrunk ON debtor.debtor_id = debtortrunk.debtor_id 
    JOIN receipt ON debtor.customer_id = receipt.customer_id AND debtor.deb_id = receipt.deb_id
WHERE
    receipt.created >= '24.01.2018' AND
    receipt.created <= '28.01.2018'
GROUP BY
    company.company_id,   
    company.companyname_1,   
    customer.customer_id,   
    customer.customername_1

如果您将聚合函数与 group by 一起使用，则 distinct 没有意义，因此可能会被删除。

Answer 2

你可以用 LEFT JOIN 做你想做的事，在 SELECT 中没有条件逻辑：

SELECT co.company_id, co.companyname_1,   
       cu.customer_id, cu.customername_1,
       COUNT(r.receipt_id) as inpayment
FROM company co JOIN
     customer cu
     ON co.company_id = cu.company_id JOIN
     debtor d
     ON cu.customer_id = d.customer_id JOIN
     debtortrunk dt
     ON d.debtor_id = dt.debtor_id LEFT JOIN
     receipt r
     ON d.customer_id = r.customer_id AND
        d.deb_id = r.deb_id AND
        r.table_name = 'PAYMENT'
WHERE r.created >= DATE '2018-01-24' AND
      r.created <= DATE '2018-01-28'
GROUP BY co.company_id, co.companyname_1,   
         cu.customer_id, cu.customername_1;

备注：

您可能不需要 debtortrunk table。它似乎没有在查询中使用。
使用 table 别名，使查询更易于编写和阅读。
使用DATE引入日期常量。这样，文字值就有了正确的类型。

Answer 3

ORA-00979: not a group by expression 表示在您的 SELECT 中有一些表达式未作为组表达式包含，也未参与聚合函数。在这种情况下，它肯定是 receipt.table_name 引用。

最直接的解决方案是将其显式包含为聚合字段：

GROUP BY
company.company_id,   
company.companyname_1,   
customer.customer_id,   
customer.customername_1,
receipt.table_name

在 Oracle SQL 中使用 DECODE 进行 GROUP BY (ORA-00979)

GROUP BY with DECODE in Oracle SQL (ORA-00979)

sql

oracle

group-by

decode

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