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How To Diagnose And Fix Incorrect Post Comment Counts In WordPress


Posted by Artem Russakovskii on March 21st, 2010 in Wordpress

Updated: September 16th, 2012

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Introduction

If your WordPress comment counts got messed up, whether because of a plugin (I'm talking about you, DISQUS) or you messed with your database manually and did something wrong (yup, that's what I just did), fear not – I have a solution for you.

But first, a little background.

Comment Counts In WordPress

Here's how comment counts work in WP:

  • Posts live in a table called wp_posts and each has an ID.
  • Comments reside in a table called wp_comments, each referring to an ID in wp_posts.
  • However, to make queries faster, the comment count is also cached in the wp_posts table, rather than getting calculated on every page load.
    If this count ever gets out of sync with
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30

Swapping Column Values in MySQL


Posted by Artem Russakovskii on February 17th, 2009 in Databases, Linux, MySQL, Programming

Updated: September 16th, 2012

Today I had to swap 2 columns in one of my MySQL tables. The task, which seems easily accomplishable by a temp variable, proved to be a bit harder to complete. But only just a bit.

Here are my findings:

  1. The

    UPDATE swap_test SET x=y, y=x;

    approach doesn't work, as it'll just set both values to y.

    PostgreSQL seems to handle this query differently, as it apparently uses the old values throughout the whole query. [Reference]
  2. Here's a method that uses a temporary variable. Thanks to Antony from the comments for the "IS NOT NULL" tweak. Without it, the query works unpredictably. See the table schema at the end of the post. This method doesn't swap the values

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