Fix wordpress comment and category counts after import, by quarkin: https://wordpress.org/support/topic/fix-comment-and-category-counts-after-import

fix-wordpress-post-counts.php

<?php
// Place this script in a page template and navigate to it.  Script will correct counts for comments and categories.
include("wp-config.php");

if (!mysql_connect(DB_HOST, DB_USER, DB_PASSWORD)) {  die('Could not connect: ' . mysql_error());  }
if (!mysql_select_db(DB_NAME)) {  die('Could not connect: ' . mysql_error());  }

$result = mysql_query("SELECT term_taxonomy_id FROM ".$table_prefix."term_taxonomy");
while ($row = mysql_fetch_array($result)) {
  $term_taxonomy_id = $row['term_taxonomy_id'];
  echo "term_taxonomy_id: ".$term_taxonomy_id." count = ";
  $countresult = mysql_query("SELECT count(*) FROM ".$table_prefix."term_relationships WHERE term_taxonomy_id = '$term_taxonomy_id'");
  $countarray = mysql_fetch_array($countresult);
  $count = $countarray[0];
  echo $count."<br />";
 mysql_query("UPDATE ".$table_prefix."term_taxonomy SET count = '$count' WHERE term_taxonomy_id = '$term_taxonomy_id'");
		}

$result = mysql_query("SELECT ID FROM ".$table_prefix."posts");
while ($row = mysql_fetch_array($result)) {
  $post_id = $row['ID'];
  echo "post_id: ".$post_id." count = ";
  $countresult = mysql_query("SELECT count(*) FROM ".$table_prefix."comments WHERE comment_post_ID = '$post_id' AND comment_approved = 1");
  $countarray = mysql_fetch_array($countresult);
  $count = $countarray[0];
  echo $count."<br />";
  mysql_query("UPDATE ".$table_prefix."posts SET comment_count = '$count' WHERE ID = '$post_id'");
		}
?>