在日期的Where子句中使用案例

Question

我目前有这个WHERE子句，其中包含以下参数。

WHERE 
    Project ID=110
    AND ((CAST(saa.Date AS DATE) >= '09/24/2014' AND CAST(saa.Date AS DATE) <= '09/24/2014') OR saa.Date IS NULL))

这里最棘手的部分是saa.Date is NULL部分将提取所有日期中的所有Null值（这是多余的），我只想使用以下Date Range作为Null值

(
        (CAST(sa.StartDateTime AS DATE) >= '09/24/2014' AND CAST(sa.StartDateTime AS DATE) <= '09/24/2014')
        OR
        (CAST(sa.EndDateTime AS DATE) >= '09/24/2014' AND CAST(sa.EndDateTime AS DATE) <= '09/24/2014')
)

所以我试图弄清楚如何创建一个可以正常工作的CASE语句，就像IF saa.Date为NULL然后[使用上面的日期范围参数]

Answer 1

我将以@AHiggins为答案，但会提高性能和可读性

-可贴性

-避免cast

- 使用between

WHERE 
    ProjectID=110 AND 
     (
      (
        saa.Date between '09/24/2014 00:00:00.000' AND '09/24/2014 23:59:59.999'
      ) OR 
      (
        saa.Date IS NULL AND
         (
            sa.StartDateTime between '09/24/2014 00:00:00.000' AND  '09/24/2014 23:59:59.999'
         ) OR
         (
            sa.EndDateTime between  '09/24/2014 00:00:00.000' AND '09/24/2014 23:59:59.999'
         )
      )
     )     

确保您在日期列上有索引

Answer 2

如果我没看错，您应该能够使用布尔逻辑和几百万个括号来做到这一点：

编辑：在@horaciux的答案的评论中注意到有一个问题，意识到我们实际上还需要几个括号。 我已经借回了代码，并在下面添加了其他功能。

WHERE 
    ProjectID=110 AND 
     (
      (
        saa.Date between '09/24/2014 00:00:00.000' AND '09/24/2014 23:59:59.999'
      ) OR 
      (
        saa.Date IS NULL AND
         ( -- need to wrap the next two conditions in a single set of parentheses
          (
            sa.StartDateTime between '09/24/2014 00:00:00.000' AND  '09/24/2014 23:59:59.999'
          ) OR
          (
            sa.EndDateTime between  '09/24/2014 00:00:00.000' AND '09/24/2014 23:59:59.999'
          )
         )
      )
     ) 

Answer 3

你知道

    >= '09/24/2014' 
AND <= '09/24/2014' 

与= '09 / 24/2014'相同

where ProjectID=110 
  AND CAST(saa.Date AS DATE) = '09/24/2014' 
   OR (
        saa.Date IS NULL 
        AND
            ( 
              CAST(sa.StartDateTime AS DATE) = '09/24/2014'
              OR
              CAST(sa.EndDateTime AS DATE)   = '09/24/2014' 
            )              
      )

这比强制转换更有效：

DATEADD(dd, DATEDIFF(dd, 0, COL),0)  

但是Horaciux的答案更加有效

Answer 4

尝试这个

(
        (CAST(ISNULL(sa.StartDateTime, '09/24/2014') AS DATE) >= '09/24/2014' AND CAST(ISNULL(saa.StartDateTime, '09/24/2014') AS DATE) <= '09/24/2014')
)