Question

这是我的代码：

SELECT CASHIER_ID AS SERVER, CONVERT(VARCHAR(10),[DATETIME],111) AS DATE, 
  SUM(GRAND_TOTAL) AS TOTAL_SALES, 
  SUM(NUM_PEOPLE_PARTY) AS NUMBER_SERVED,  
  SUM(GRAND_TOTAL) / SUM(NUM_PEOPLE_PARTY) AS CASHPERCUSTOMER 
FROM INVOICE_TOTALS 
WHERE [DATETIME] >= '2012-06-01' 
GROUP BY CASHIER_ID, CONVERT(VARCHAR(10),[DATETIME],111)

除了：

之外，一切都与代码完美配合

SUM(GRAND_TOTAL) / SUM(NUM_PEOPLE_PARTY) AS CASHPERCUSTOMER

部。如果我把这条线拿出去，那么一切都很完美，如果我把它放入，我会收到以下错误：

消息：无法检索数据表。
SELECT CASHIER_ID AS SERVER，...上面的其余查询...

堆栈跟踪：
......不相关的堆栈跟踪......

消息：遇到零除错误。

堆栈跟踪：
  ...不相关的堆栈跟踪...

这是使用SQL Server的餐厅销售点（POS）系统内的SQL。有什么想法可能会发生吗？

Answer 1

您需要以这种方式运行查询，并告诉我们是否有任何结果：

SELECT CASHIER_ID AS SERVER, 
  CONVERT(VARCHAR(10),[DATETIME],111) AS DATE, 
  SUM(GRAND_TOTAL) AS TOTAL_SALES,  
  SUM(NUM_PEOPLE_PARTY) AS NUMBER_SERVED
FROM INVOICE_TOTALS 
WHERE [DATETIME] >= '2012-06-01' 
GROUP BY CASHIER_ID, CONVERT(VARCHAR(10),[DATETIME],111) 
HAVING SUM(NUM_PEOPLE_PARTY) = 0;

如果有结果，那么显然您的查询需要满足它们。例如：

SELECT SERVER, [DATE], TOTAL_SALES, NUMBER_SERVED,
  CASHPERCUSTOMER = TOTAL_SALES / NULLIF(NUMBER_SERVED, 0)
FROM
(
  SELECT CASHIER_ID AS SERVER, 
    CONVERT(VARCHAR(10),[DATETIME],111) AS DATE, 
    SUM(GRAND_TOTAL) AS TOTAL_SALES,  
    SUM(NUM_PEOPLE_PARTY) AS NUMBER_SERVED
  FROM INVOICE_TOTALS 
  WHERE [DATETIME] >= '2012-06-01' 
  GROUP BY CASHIER_ID, CONVERT(VARCHAR(10),[DATETIME],111) 
);

但你应该弄清楚为什么有0的结果，因为这没有多大意义。

Answer 2

分开前检查0：

SELECT
    ...,
    CASE WHEN SUM(NUM_PEOPLE_PARTY) = 0
         THEN NULL
         ELSE SUM(GRAND_TOTAL) / SUM(NUM_PEOPLE_PARTY) END AS CASHPERCUSTOMER,
    ...

使用NULLIF获得相同的结果：

SELECT
    ...,
    CASE SUM(GRAND_TOTAL) / NULLIF(SUM(NUM_PEOPLE_PARTY), 0) AS CASHPERCUSTOMER,
    ...

尝试划分数据时除以零错误

2 个答案: