我有一个很长的查询是切换资源,并需要重写它。 它的一个显而易见的问题是在where子句中使用“not in”。 我最初的想法是重写它,废除所有的自联接,并在子查询上做一个“不存在”。有没有想过这样做,或者比这更有效的想法?一个更好的方法来写这个MySQL选择查询
这里的查询:
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
WOAH!这是很多... –
对不起,我不清楚这些连接点是什么.. – Kermit
您正试图从同一张表中获得6个不同的成员ID?你能提供关于这个查询目标的更多信息吗? – Jeffrey