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我有一个查询,我转身成功的视图。但site_phrase sp
表似乎没有使用列并遍历表中的所有记录。这是为什么?下面是该查询:为什么我的查询不使用这个索引?
EXPLAIN SELECT
`p`.`id` AS `id`,
`p`.`text` AS `phrase`,
`p`.`ignored` AS `ignored_phrase`,
`p`.`client_id` AS `client_id`,
`s`.`id` AS `site_id`,
`s`.`sub_domain` AS `sub_domain`,
`s`.`competitor` AS `competitor`,
`s`.`ignored` AS `ignored_site`,
`pc`.`id` AS `pc_id`,
`pc`.`name` AS `pc_name`,
`psc`.`id` AS `psc_id`,
`psc`.`name` AS `psc_name`,
`p`.`volume` AS `volume`,
MIN(`pos`.`position`) AS `position`,
`pos`.`id` AS `pos_id`
FROM `client` c
JOIN client_site cs ON cs.client_id = c.id
JOIN site s ON s.id = cs.site_id
JOIN site_phrase sp ON sp.site_id = s.id
JOIN phrase p ON p.id = sp.phrase_id
JOIN `position` pos ON pos.phrase_id = sp.phrase_id
AND pos.site_id = sp.site_id
LEFT JOIN `phrase_sub_category` `psc`
ON `psc`.`id` = `p`.`phrase_sub_category_id`
LEFT JOIN `phrase_category` `pc`
ON `pc`.`id` = `psc`.`phrase_category_id`
GROUP BY `p`.`id`,`s`.`id`,`serp`.`id`
ORDER BY `p`.`id`,`pos`.`position`
,这里是输出的屏幕截图,上面的查询得到,当我说明/描述它 http://img827.imageshack.us/img827/3336/indexsql.png
无论我如何改变上述以及如何表的顺序,他们第一张或第二张桌子似乎总是在做某种表格扫描。在截图的例子中,问题表是sp
。这些表是innoDB类型,并且在我加入的所有表上都有适当的索引和外键。任何见解都会有所帮助。
什么是查询? – FrustratedWithFormsDesigner 2010-10-01 17:07:56
上面所有连接的人。我刚刚删除了我选择的字段。解释选择.....就是这样 – Nathan 2010-10-01 17:09:33