优化和清理 WordPress 数据库：DIY 指南

-- Optimize commonly used WordPress tables to reduce fragmentation
OPTIMIZE TABLE wp_posts, wp_postmeta, wp_options, wp_usermeta, wp_comments;

-- Start the transaction
START TRANSACTION;

-- Remove transients (temporary data)
DELETE FROM wp_options WHERE option_name LIKE '_transient_%' OR option_name LIKE '_site_transient_%';

-- Remove post revisions
DELETE FROM wp_posts WHERE post_type = 'revision';

-- Remove auto-drafts
DELETE FROM wp_posts WHERE post_status = 'auto-draft';

-- Remove orphaned post meta (meta data for non-existent posts)
DELETE pm FROM wp_postmeta pm LEFT JOIN wp_posts wp ON wp.ID = pm.post_id WHERE wp.ID IS NULL;

-- Remove orphaned comment meta
DELETE FROM wp_commentmeta WHERE comment_id NOT IN (SELECT comment_id FROM wp_comments);

-- Remove spam and trashed comments
DELETE FROM wp_comments WHERE comment_approved IN('spam', 'trash');

-- Remove orphaned term relationships (tags, categories linked to non-existent posts)
DELETE tr FROM wp_term_relationships tr LEFT JOIN wp_posts wp ON wp.ID = tr.object_id WHERE wp.ID IS NULL;

-- Remove expired user sessions
DELETE FROM wp_usermeta WHERE meta_key = '_wp_session_expires' AND meta_value < UNIX_TIMESTAMP();

-- Remove old, non-autoloading plugin options
DELETE FROM wp_options WHERE autoload = 'no';

-- Identify unattached media files (this won't delete the files, just shows them)
SELECT * FROM wp_posts WHERE post_type = 'attachment' AND post_parent = 0;

-- Commit the transaction (to apply changes)
COMMIT;

-- Rollback the transaction if you don't want to commit the changes
ROLLBACK;