选择语句以针对2个变量检查​​多行

Question

我有下表：

alertID inspectorID datelive                dateread
1       none       2012-11-06 10:36:03.350  NULL
2       none       2012-11-06 10:36:25.043  NULL
3       none       2012-11-06 10:36:42.433  NULL
1       31030      2012-11-06 10:37:19.193  2012-06-11 10:34:47.000

我想选择没有检查员ID的警报以及警报ID与具有检查者ID的警报ID不匹配，即检查员已读取警报1所以我只希望它返回警报2 ＆安培; 3

使用经典ASP和MS-SQL

Answer 1

试试这个

Select * From Alerts
Where AlertId Not In (Select AlertID From Alerts Where InspectorID IS NOT NULL)

我们的想法是知道哪些ID具有InspectorID，然后使用NOT IN

从结果中排除它们

Answer 2

SELECT *
FROM alertsTable
WHERE inspectorID IS NULL
AND alertID NOT IN (SELECT alertID FROM alertsTable where inspectorID IS NOT NULL)

Answer 3

Select * From Table
Where alertID Not In 
(Select alertID From Table Where inspectorID != 'none')