鲜明不在程序工作在MySQL

Question

if(eventType=1 ) then 
    set @Whereclause=CONCAT(@Whereclause," and scheduleDate > ",@currentdate, " order by scheduleDate "); 
    end if; 
    if(eventType=0 ) then 
    set @Whereclause=CONCAT(@Whereclause," and scheduleDate < ",@currentdate," order by scheduleDate desc "); 
    end if; 
    if(eventType=-1) then 
     set @Whereclause=CONCAT(@Whereclause," order by scheduleDate desc "); 
     end if; 

    set @SqlQuery= CONCAT(" 
select distinct(event_schedule_id) 
from TEST_EVENT_LIST_VIEW ", @Whereclause); 


set totalcountquery=@Whereclause; 

    if(offsetvalue<recordlimit) then 

     set @QueryfforPagination=CONCAT(@SqlQuery," limit ",recordlimit); 
    PREPARE querystatement FROM @QueryfforPagination; 
    EXECUTE querystatement; 
    DEALLOCATE PREPARE querystatement; 


    else 
     set @QueryfforPagination=CONCAT(@SQLQuery," limit ",recordlimit," offset ",offsetvalue); 
     PREPARE querystatement FROM @QueryfforPagination; 
     EXECUTE querystatement; 
     DEALLOCATE PREPARE querystatement; 

    end if; 


END 

这是我的程序查询时，我尝试执行使用select distinct（event_schedule_id）此过程中它的显示错误

错误代码：3065表达式＃1的ORDER BY子句不在SELECT 列表中，引用列'TEST_EVENT_LIST_VIEW.scheduleDate'，它不是在SELECT列表中的 ;这是不符合DISTINCT

当我删除不同然后其工作正常，请建议我是谁来解决这个问题。

Answer 1

在使用DISTINCT和ORDER BY那么我们必须在SELECT列表如下有ORDER BY列：

要么：

order by event_schedule_id desc 

OR

set @SqlQuery= CONCAT(" 
select distinct event_schedule_id, scheduleDate 
from TEST_EVENT_LIST_VIEW ", @Whereclause); 

SELECT DISTINCT A FROM myTable ORDER BY B --It doesn't work 
SELECT DISTINCT A FROM myTable ORDER BY A --It works 
SELECT DISTINCT A, B FROM myTable ORDER BY A, B --It works 
SELECT DISTINCT A, B FROM myTable ORDER BY B --It works 

如果我们从上面删除了DISTINCT，然后所有的陈述都没有任何复杂性。