求教一条SQL语句 在线等啊
string strk = "select top 20 MobileTheme.ThemeName ,MobileTheme .DownLoadUrl,MobileThemePreviews .Preview from MobileTheme join MobileThemePreviews on MobileThemePreviews.MobileThemeId=MobileTheme.Id order by Downloads desc";


为什么我这条SQL语句读取出来的数据 同一条数据会显示两次呢？ 要怎样修改呢？ 求教大神

[解决办法]
select distinct ....
[解决办法]
select
top 20 MobileTheme.ThemeName ,
MobileTheme .DownLoadUrl,
MobileThemePreviews .Preview
from MobileTheme join MobileThemePreviews
on MobileThemePreviews.MobileThemeId=MobileTheme.Id group by MobileTheme.ThemeName ,
MobileTheme .DownLoadUrl,
MobileThemePreviews .Preview order by Downloads desc
加个 group by
[解决办法]