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WordPress: How to Clean up Meta Data

This article will explain how to clean up meta data in a WordPress database.



Important: Backup your database before performing any of the steps in this article. You will be deleting data from the database. Accidentally deleting the wrong information may require restoring your database from a backup. If you are unsure how to backup your database please see How to Backup a MySQL Database

What You Need

To complete this tutorial, you will need to know the following information:

Open The Database in phpMyAdmin

  1. Login to your account at my.Bluehost.com
  2. Open the cPanel section of your account.
  3. On the cPanel, under Databases, click phpMyAdmin
  4. Log in with your cPanel username and password (if prompted). 
  5. Along the left-hand side of the screen, click on the database associated with your WordPress installation.
    Select Database

Remove Rows With No ID

  1. Note the prefix attached to your database tables. In our example database, all table names begin with wp_rfrz_. This is our database prefix; yours will differ.
    Database Table Prefix
  2. Click on the SQL tab.
    SQL Tab

Comment Meta Data

These steps explain how to clear the comment meta data.

  1. Copy and paste this code into the textbox:
      SELECT * FROM your_prefixcommentmeta WHERE comment_id NOT IN ( SELECT comment_id FROM your_prefix_comments );
      DELETE FROM your_prefix_commentmeta WHERE comment_id NOT IN ( SELECT comment_id FROM your_prefix_comments );
      SELECT * FROM your_prefix_commentmeta WHERE meta_key LIKE '%akismet%'; 
      DELETE FROM your_prefix_commentmeta WHERE meta_key LIKE '%akismet%';
  2. Replace your_prefix_ with your database prefix.
    Replace Prefix - Go
  3. Click the go button.

Post Meta Data

These steps explain how to clear the post meta data.

  1. Copy and paste this code into the textbox:
    SELECT * FROM your_prefix_postmeta pm LEFT JOIN your_prefix_posts wp ON wp.ID = pm.post_id WHERE wp.ID IS NULL;
    DELETE pm FROM wp_postmeta pm LEFT JOIN your_prefix__posts wp ON wp.ID = pm.post_id WHERE wp.ID IS NULL;
  2. Replace your_prefix_ with your database prefix.
  3. Click the go button.

Optimize The Post and Comment Tables

  1. At the top of phpMyAdmin, click the structure tab.
    Structure
  2. Select the comments, commentmeta, posts, and postmeta tables.
    Optimize Database
  3. In the drop-down menu labeled With Selected, choose Optimize Table.
The tables should now have unnecessary metadata removed. If you encounter any issues with the website after this procedure, consider restoring your database using your backup.