无法摆脱重复

Question

我有我的疑问：

SELECT   t.nCitiesId
    ,t.tmDate
    ,t.strShortWeekdayName
    ,t.nIsHoliday
FROM    #temp AS t
WHERE   1 = 1
AND     t.nCitiesId = 104
AND     t.tmDate = '2014-06-08'
GROUP BY t.tmDate, t.nCitiesId, t.strShortWeekdayName, t.nIsHoliday

这会生成以下结果：

nCitiesId         tmDate              strShortWeekdayName   nIsHoliday
104       2014-06-08 00:00:00.000            SUN                0
104       2014-06-08 00:00:00.000            SUN                1

我的问题是当 nCitiesId 和 tmDate 相等时，我不希望 nIsHoliday = 0 的那个消失。

我怎样才能顺利地做到这一点？

Answer 1

尝试使用 having 子句：

SELECT   t.nCitiesId
    ,t.tmDate
    ,t.strShortWeekdayName
    ,t.nIsHoliday
FROM    #temp AS t
WHERE   1 = 1
AND     t.nCitiesId = 104
AND     t.tmDate = '2014-06-08'
GROUP BY t.tmDate, t.nCitiesId, t.strShortWeekdayName, t.nIsHoliday
having max(t.nIsHoliday)

Answer 2

选择具有最高价值的t.nIsHoliday：

SELECT t.nCitiesId
      ,t.tmDate
      ,t.strShortWeekdayName
      ,max(t.nIsHoliday)
FROM   #temp AS t
WHERE  t.nCitiesId = 104
AND    t.tmDate = '2014-06-08'
GROUP BY t.nCitiesId, t.tmDate, t.strShortWeekdayName