Question

我有以下数据结构：

P_ID    EVSSMIN EVSSMAX TDMIN   TDMAX   WARD    SYRINGE_ID   COMBINE_WITH   CUSTOM_CONCENTRATION
1003    0   20  125 250 2ZKG    1021038
    44444444    5
1003    20  60  125 250 2ZKG    1021037
    44444444    5

通常我使用以下查询结果。

[QUERY 1]

SELECT * 
FROM [definities] 
WHERE 160 BETWEEN [TDMIN] AND [TDMAX] AND [WARD] = '2ZKG' AND [P_ID]=` 1003;

表格中的最后一列可以包含一个高于0的值。高于它。

通常我想运行下面的查询而不是上面的查询。

[QUERY 2]

SELECT * FROM [definities] 
WHERE 160 BETWEEN [TDMIN] AND [TDMAX] 
AND CAST(160 as decimal) / [CUSTOM_CONCENTRATION]) BETWEEN EVSSMIN AND EVSMAX 
AND [WARD] = '2ZKG' -- AND [P_ID]= 1003;

如您所见，查询通过将值除以[CUSTOM_CONCENTRATION]）值来计算值160。比它在EVVSMIN和EVSSMAX之间匹配，并且值160在TDMIN和TDMAX之间匹配。通常，当[CUSTOM_CONCENTRATION]列包含值为higer然后为0时，查询2将正常工作。

问题是当[CUSTOM_CONCENTRATION]列不包含高于0的值时，查询无法返回记录。这意味着必须根据[CUSTOM_CONCENTRATION]值更改查询或其他内容。我可以在C＃代码中解决这个问题，但简洁的方法是能够将此作为一个查询，根据值返回我的确切记录，而不是我需要迭代的多个记录并使用if语句检查它。

Answer 1

假设您想要[CUSTOM_CONCENTRATION]值为零或更低时的第一个查询，否则需要第二个查询，您可以使用UNION ALL对两个查询都有另一个限制：

SELECT * FROM [definities] 
WHERE 160 BETWEEN [TDMIN] AND [TDMAX] AND [WARD] = '2ZKG' AND [P_ID]=` 1003
AND [CUSTOM_CONCENTRATION] <= 0

UNION ALL

SELECT * FROM [definities] 
WHERE 160 BETWEEN [TDMIN] AND [TDMAX] 
AND CAST(160 as decimal) / [CUSTOM_CONCENTRATION]) BETWEEN EVSSMIN AND EVSMAX 
AND [WARD] = '2ZKG' -- AND [P_ID]= 1003
AND [CUSTOM_CONCENTRATION] > 0;

另一种解决方案，更优雅的是：

SELECT * FROM [definities] 
WHERE 160 BETWEEN [TDMIN] AND [TDMAX] AND [WARD] = '2ZKG'
AND (([P_ID]=` 1003
      AND [CUSTOM_CONCENTRATION] <= 0)
     OR
     (CAST(160 as decimal) / [CUSTOM_CONCENTRATION]) BETWEEN EVSSMIN AND EVSMAX
      AND AND [CUSTOM_CONCENTRATION] > 0));

Answer 2

也许是这样的：

SELECT * FROM [definities] WHERE 160 BETWEEN [TDMIN] AND [TDMAX] AND
 ( case when [CUSTOM_CONCENTRATION] = 0 then EVSSMIN 
         else CAST(160 as decimal) / [CUSTOM_CONCENTRATION]) end
            BETWEEN EVSSMIN AND EVSMAX )
         AND [WARD] = '2ZKG'

SQL Server基于记录值的查询

2 个答案: