选择“语句查询”以排除具有重复值的行

Question

我需要使用select语句进行SQL查询，该语句排除具有相同Start_Time，End_Time和ReasonCode

的重复行

EventID       Start_Time         End_Time             ReasonCode 

 122         1/3/2015 0:27      1/3/2015 1:32      No Trouble Found
 123         1/3/2015 0:27      1/3/2015 1:32      No Trouble Found
 124         1/3/2015 0:27      1/3/2015 1:32      No Trouble Found
 125         1/31/2015 14:35    1/31/2015 14:56    LinkupDown

结果输出如下：

EventID       Start_Time         End_Time             ReasonCode 

 122         1/3/2015 0:27      1/3/2015 1:32      No Trouble Found
 125         1/31/2015 14:35    1/31/2015 14:56    LinkupDown

感谢帮助人员。

Answer 1

将group by和min函数应用于查询将创建所需的结果集。 SQL Fiddle Demo。

select min(eventid) EventID, DATE_FORMAT(Start_Time,'%m/%d/%Y %H:%i') Start_Time, DATE_FORMAT(End_Time,'%m/%d/%Y %H:%i') End_Time, ReasonCode
from mytable
group by ReasonCode
order by eventid