我有一个很长的查询正在占用资源并且需要重写它。它的明显问题是在 where 子句中使用了“not in”。我最初的想法是重写它,取消所有自连接并在子查询上执行“不存在”。关于这样做的任何想法,或者比那个更有效的想法?
这是查询:
SELECT a.referenceid,
a.memberid AS d1,
b.memberid AS d2,
c.memberid AS d3,
d.memberid AS d4,
e.memberid AS d5,
f.memberid AS d6
FROM jos_comprofiler_members AS a FORCE INDEX (aprm)
LEFT JOIN jos_comprofiler_members AS b FORCE INDEX (aprm)
ON a.memberid = b.referenceid
AND b.accepted = 1
AND b.pending = 0
LEFT JOIN jos_comprofiler_members AS c FORCE INDEX (aprm)
ON b.memberid = c.referenceid
AND c.accepted = 1
AND c.pending = 0
LEFT JOIN jos_comprofiler_members AS d FORCE INDEX (pamr)
ON c.memberid = d.referenceid
AND d.accepted = 1
AND d.pending = 0
LEFT JOIN jos_comprofiler_members AS e FORCE INDEX (pamr)
ON d.memberid = e.referenceid
AND e.accepted = 1
AND e.pending = 0
LEFT JOIN jos_comprofiler_members AS f FORCE INDEX (pamr)
ON e.memberid = f.referenceid
AND f.accepted = 1
AND f.pending = 0
WHERE a.referenceid = 1593
AND a.accepted = 1
AND a.pending = 0
AND f.memberid = 1593
AND b.memberid NOT IN ( 1593, a.memberid )
AND c.memberid NOT IN ( 1593, a.memberid, b.memberid )
AND d.memberid NOT IN ( 1593, a.memberid, b.memberid, c.memberid )
AND e.memberid NOT IN (
1593, a.memberid, b.memberid, c.memberid, d.memberid )
AND f.memberid NOT IN ( 1593, a.memberid, b.memberid, c.memberid,
d.memberid, e.memberid )
LIMIT 0, 1