MySQL子查詢組按

Question

我有一個查詢，顯示基於一個人的id（運動員）的比賽結果列表。我查詢了數據庫，以便按時間（性能）和事件（eventid）順序列出人員的比賽，但我努力將其設置爲子查詢，以便我可以將結果分組後，以最快的速度離開我每個eventid的性能。這是我到目前爲止：

$id = $_GET['id']; 
$query = sprintf("SELECT events.eventcode, meetings.meetingid, meetings.meetingname, meetings.location, meetings.meetingdate, DATE_FORMAT(meetings.meetingdate,'%%d %%b %%Y') AS date, results.performance, results.unit, results.wind, agegroups.agegroup 
FROM results 
JOIN athletes ON athletes.athleteid = results.athleteid 
JOIN meetings ON meetings.meetingid = results.meetingid 
JOIN events ON events.eventid = results.eventid 
JOIN agegroups ON agegroups.agegroupid = results.agegroupid 
WHERE results.athleteid='$id' AND events.eventtype = 'track' ORDER BY results.eventid asc, results.performance asc, meetings.meetingdate desc"); 

這工作正常，並以正確的順序顯示所有相關的條目。然後我嘗試將它轉換爲子查詢，以便我可以使用GROUP BY，但沒有成功。這是我試圖去用它：

$id = $_GET['id']; 
$query = sprintf("SELECT * FROM (SELECT events.eventcode, meetings.meetingid, meetings.meetingname, meetings.location, meetings.meetingdate, DATE_FORMAT(meetings.meetingdate,'%%d %%b %%Y') AS date, results.performance, results.unit, results.wind, agegroups.agegroup 
FROM results 
JOIN athletes ON athletes.athleteid = results.athleteid 
JOIN meetings ON meetings.meetingid = results.meetingid 
JOIN events ON events.eventid = results.eventid 
JOIN agegroups ON agegroups.agegroupid = results.agegroupid 
WHERE results.athleteid='$id' AND events.eventtype = 'track' ORDER BY results.eventid asc, results.performance asc, meetings.meetingdate desc) AS t1 
GROUP BY t1.eventid"); 

然而，這給了我這一條錯誤：在「組聲明」未知列「t1.eventid」

任何幫助是極大的讚賞

Answer 1

您在子查詢中未選擇eventid。如果不在那裏，你如何分組？

SELECT events.eventid,events.eventcode, 
meetings.meetingid, meetings.meetingname, 
meetings.location, meetings.meetingdate, 
DATE_FORMAT(meetings.meetingdate,'%%d %%b %%Y') AS date, 
results.performance, results.unit, results.wind, 
agegroups.agegroup 
....... 

Answer 2

那是因爲你沒有在子查詢列，嘗試添加列子選擇：

$id = $_GET['id']; 
$query = sprintf("SELECT * FROM (SELECT events.eventid, events.eventcode, meetings.meetingid, meetings.meetingname, meetings.location, meetings.meetingdate, DATE_FORMAT(meetings.meetingdate,'%%d %%b %%Y') AS date, results.performance, results.unit, results.wind, agegroups.agegroup 
FROM results 
JOIN athletes ON athletes.athleteid = results.athleteid 
JOIN meetings ON meetings.meetingid = results.meetingid 
JOIN events ON events.eventid = results.eventid 
JOIN agegroups ON agegroups.agegroupid = results.agegroupid 
WHERE results.athleteid='$id' AND events.eventtype = 'track' ORDER BY results.eventid asc, results.performance asc, meetings.meetingdate desc) AS t1 
GROUP BY t1.eventid");