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有點麻煩,我怎麼能改變這個mysql查詢,以便如果member_results表中有行,它將運行下面的查詢,但如果沒有,那麼幾乎在下面運行查詢SUMS()和與member_results表的連接。我猜測可以用mysql中的IF語句來完成我只是不知道如何使用下面的查詢來實現。帶IF語句的MYSQL查詢
任何幫助,非常感謝。
$result = mysql_query(" SELECT m.member_id, m.teamname,
Sum(Case When r.track_id = '$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");
爲什麼不是PHP IF? –