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有点麻烦,我怎么能改变这个mysql查询,以便如果member_results表中有行,它将运行下面的查询,但如果没有,那么几乎在下面运行查询SUMS()和与member_results表的连接。我猜测可以用mysql中的IF语句来完成我只是不知道如何使用下面的查询来实现。带IF语句的MYSQL查询
任何帮助,非常感谢。
$result = mysql_query(" SELECT m.member_id, m.teamname,
Sum(Case When r.track_id = '$chosentrack' -1 AND r.track_id >= l.start_race
Then total_points Else 0 End) LastRacePoints,
Sum(Case When r.track_id <= '$chosentrack' -1 AND r.track_id >= l.start_race
Then total_points Else 0 End) TotalPoints
FROM members m
Join members_leagues l
On l.member_id = m.member_id
Join member_results r
On r.member_id = m.member_id
Where l.league_id = '$chosenleague'
Group By m.member_id
Order By TotalPoints Desc, LastRacePoints DESC, m.teamname Desc ")
or die ("Error - could not display league");
为什么不是PHP IF? –