[英]How can I improve performance of a MySQL query without changing the underlying tables?
我有一個查詢來自第三方產品的數據的應用程序。 因此,我渴望不更改表結構。
有沒有一種方法可以純粹在查詢方面提高效率?
我的查詢是:
CallsClosed.Query = @"SELECT COALESCE(ti.FIRST_NAME,'Not Assigned') AS 'Technician', COUNT(*) 'Calls_Closed'
FROM WorkOrder_Threaded wot
INNER JOIN WorkOrder wo ON wot.WORKORDERID=wo.WORKORDERID
LEFT JOIN SDUser sdu ON wo.REQUESTERID=sdu.USERID
LEFT JOIN AaaUser aau ON sdu.USERID=aau.USER_ID
LEFT JOIN WorkOrderStates wos ON wo.WORKORDERID=wos.WORKORDERID
LEFT JOIN SDUser td ON wos.OWNERID=td.USERID
LEFT JOIN AaaUser ti ON td.USERID=ti.USER_ID
WHERE (wo.COMPLETEDTIME != 0) AND (wo.COMPLETEDTIME != -1) AND (wo.COMPLETEDTIME IS NOT NULL)
AND wo.COMPLETEDTIME >= (UNIX_TIMESTAMP(TIMESTAMP('" + sdChartRange.From + @"')) * 1000)
AND wot.THD_WOID=wot.WORKORDERID
GROUP BY Technician ORDER BY 'Calls_Closed' DESC";
我已經在上面運行了JetProfiler,看來主要的罪魁禍首是wot表的大小。 (約19k行)
關於我應該從哪里開始加快查詢的任何建議? (目前大約需要4秒鍾才能運行)
EXPLAIN QUERY
結果。
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