为什么我的查询没有按预期工作？

Question

我有一个查询，我试图在其中获取不在另一个 table 中的特定值，但是当我运行查询时，我没有得到任何结果。这就是我所看到的。请让我知道出了什么问题。

原始查询：Returns 399 行

        USE TFW_DEV

    SELECT
       unitid, unitnumber
     FROM
       Units
     WHERE 
        createdon BETWEEN '2016-11-01 00:00:00' AND '2016-11-03 23:59:59'
    ORDER BY
        unitnumber

查询以查看 table 共享数据的位置：Returns 50 行

USE TFW_DEV

SELECT
   unitid, unitnumber
 FROM
   Units
 WHERE 
    createdon BETWEEN '2016-11-01 00:00:00' AND '2016-11-03 23:59:59'
    AND unitid  IN
    (
        SELECT
            unitid
        FROM
            meteraudit      
    )
ORDER BY
    unitnumber

带有 NOT IN 的最终查询：Returns 0 行

USE TFW_DEV

SELECT
   unitid, unitnumber
 FROM
   Units
 WHERE 
    createdon BETWEEN '2016-11-01 00:00:00' AND '2016-11-03 23:59:59'
    AND unitid NOT IN
    (
        SELECT
            unitid
        FROM
            meteraudit      
    )
ORDER BY
    unitnumber

我希望最终查询 return 349 行正确吗？如果不是，我做错了什么？谢谢，

Answer 1

当 Sub-Query

返回 NULL 值时，

NOT IN 失败

使用NOT EXISTS

SELECT unitid, 
       unitnumber 
FROM   units U 
WHERE  createdon BETWEEN '2016-11-01 00:00:00' AND '2016-11-03 23:59:59' 
       AND NOT EXISTS (SELECT 1 
                       FROM   meteraudit M 
                       WHERE  U.unitid = M.unitid) 
ORDER  BY unitnumber

为什么我的查询没有按预期工作？

Why is my query not working like expected?

tsql

sql-server

notin