SUM()基于与SELECT不同的条件 [英] SUM() based on a different condition to the SELECT
问题描述
您好,有一种方法可以根据与SELECT语句其余部分不同的条件来执行SUM(total_points),因此我希望对于$ chosentrack中< =的每一行都使用SUM(total_points)?但SELECT语句的其余条件必须满足以下条件.我需要将它们全部归还...........
非常感谢您的帮助.
SELECT
members.member_id,
members.teamname,
SUM(total_points) as total_points,
total_points as last_race_points
FROM
members,
members_leagues,
member_results
WHERE
members.member_id = members_leagues.member_id
AND members_leagues.league_id = '$chosenleague'
AND member_results.track_id = '$chosentrack'
AND members_leagues.start_race = '$chosentrack'
AND member_results.member_id = members_leagues.member_id
GROUP BY
members.member_id
ORDER BY
member_results.total_points DESC,
last_race_points DESC,
members.teamname DESC
您还可以将总和放入case语句中,其中case评估其他条件,然后仅对条件为true的那些记录求和.
SELECT m.member_id, m.teamname,
Sum(Case When r.track_Id = '$chosentrack'
Then total_points Else 0 End) TotalChosenTrackPoints,
Sum(Case When r.track_Id < '$chosentrack'
Then total_points Else 0 End) TotalLessThanChosenTrackPoints,
total_points as last_race_points
FROM members m
Join members_leagues l
On l.member_id = m.member_id
Join member_results r
On r.member_id = m.member_id
Where l.league_id = '$chosenleague'
And l.start_race = '$chosentrack'
Group By m.member_id
Order By r.total_points Desc,
last_race_points Desc, m.TeamName Desc
Hi is there a way that I can do the SUM(total_points) based on a different condition to the rest of the SELECT statement, so I want the SUM(total_points) for every row which is <= to $chosentrack? but the rest of the conditions of the SELECT statement to be what they are below. I need them to all be returned together..as I am populating a league table.
Thanks a lot for any help.
SELECT
members.member_id,
members.teamname,
SUM(total_points) as total_points,
total_points as last_race_points
FROM
members,
members_leagues,
member_results
WHERE
members.member_id = members_leagues.member_id
AND members_leagues.league_id = '$chosenleague'
AND member_results.track_id = '$chosentrack'
AND members_leagues.start_race = '$chosentrack'
AND member_results.member_id = members_leagues.member_id
GROUP BY
members.member_id
ORDER BY
member_results.total_points DESC,
last_race_points DESC,
members.teamname DESC
You can also put the sum inside a case statement, where the case evaluates the other condition, and then only sum thoses records where the condition is true...
SELECT m.member_id, m.teamname,
Sum(Case When r.track_Id = '$chosentrack'
Then total_points Else 0 End) TotalChosenTrackPoints,
Sum(Case When r.track_Id < '$chosentrack'
Then total_points Else 0 End) TotalLessThanChosenTrackPoints,
total_points as last_race_points
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 = '$chosenleague'
And l.start_race = '$chosentrack'
Group By m.member_id
Order By r.total_points Desc,
last_race_points Desc, m.TeamName Desc
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