WordPress是一套非常好的CSM（或者叫做BLOG）系统，其实它早已经超越了BLOG系统。功能强大，操作简单，插件繁多。下面是对WordPress操作的18条WordPress SQL查询语句（不仅仅是查询语句），还有删除和修改语句。
1. 删除所有未使用的标签
DELETE a,b,c
FROM wp_terms AS a
LEFT JOIN wp_term_taxonomy AS c ON a.term_id = c.term_id
LEFT JOIN wp_term_relationships AS b ON b.term_taxonomy_id = c.term_taxonomy_id
WHERE c.taxonomy = 'post_tag' AND c.count = 0
2. 删除所有文章修订版本(Revisions)以及它们的Meta数据
DELETE a,b,c
FROM wp_posts a
LEFT JOIN wp_term_relationships b ON (a.ID = b.object_id)
LEFT JOIN wp_postmeta c ON (a.ID = c.post_id)
WHERE a.post_type = 'revision'
3. 更改WordPress地址和首页地址
UPDATE wp_options
SET option_value = replace(option_value, 'http://www.旧网址.com', 'http://www.新网址.com')
WHERE option_name = 'home' OR option_name = 'siteurl'
4. 更改文章的GUID
UPDATE wp_posts
SET guid = REPLACE (guid, 'http://www.旧网址.com', 'http://www.新网址.com')
5. 更改正文中的链接地址
UPDATE wp_posts
SET post_content = REPLACE (post_content, 'http://www.旧网址.com', 'http://www.新网址.com')
6. 更新文章的Meta值
UPDATE wp_postmeta
SET meta_value = REPLACE (meta_value, 'http://www.旧网址.com', 'http://www.新网址.com'
7. 重设Admin密码
UPDATE wp_users
SET user_pass = MD5( 'new_password' )
WHERE user_login = 'admin'
8. 重设admin的用户名
UPDATE wp_users
SET user_login = 'newname'
WHERE user_login = 'admin'
9. 将作者a的文章全部转移到作者b
UPDATE wp_posts
SET post_author = 'b'
WHERE post_author = 'a'
10. 删除文章的meta标签
DELETE FROM wp_postmeta
WHERE meta_key = 'your-meta-key'
11. 导出所有评论中的邮件地址
SELECT DISTINCT comment_author_email
FROM wp_comments
12. 删除所有的Pingback
DELETE FROM wp_comments
WHERE comment_type = 'pingback'
13. 删除所有的垃圾评论
DELETE FROM wp_comments
WHERE comment_approved = 'spam'
14. 禁用所有激活的插件
UPDATE wp_options
SET option_value = ''
WHERE option_name = 'active_plugins'
15. 罗列所有未使用的Meta标签
SELECT *
FROM wp_postmeta pm
LEFT JOIN wp_posts wp ON wp.ID = pm.post_id
WHERE wp.ID IS NULL
16. 关闭旧文章的留言
UPDATE wp_posts
SET comment_status = 'closed'
WHERE post_date < '2009-01-01' AND post_status = 'publish'
17. 更新留言者的网址
UPDATE wp_comments
SET comment_author_url = REPLACE( comment_author_url, 'http://旧网址.com', 'http://新网址.com' )
18. 更新正文内所有的’target=”_blank”‘为’rel=”nofollow”‘
UPDATE wp_posts
SET post_content = REPLACE (post_content, 'target="_blank', 'rel="nofollow')
注意：在每次执行SQL语句前，请勿必备份你的WordPress数据库。