Convert all existing topics in category to wikis

[joebuhlig]

With the ability (coming soon) to make new topics wikis by default, it will likely be met with a desire to convert the existing topics in that category to wikis as well. Here’s the process:

1. Make sure you have a backup in place.

   You can do this via the UI. This is just in case something goes wrong.

2. Get the id of the category you want to edit.

   ./launcher enter app 
   rails c
   % Category.find_by(name: "Wiki Topics Category").id
   => 12
   

3. You’ll need to run SQL to update the first post of each topic in that category. This is the SQL query:

   UPDATE posts 
   SET wiki=true 
   WHERE id IN (
       SELECT p.id 
       FROM posts p 
       LEFT JOIN topics t ON p.topic_id = t.id 
       WHERE p.post_number = 1 AND t.category_id = YOUR_CATEGORY_ID);
   

   For example, if my category id is 12, then this is the command I need to run:

   ./launcher enter app 
   rails c
   % User.exec_sql("UPDATE posts SET wiki=true WHERE id IN (SELECT p.id FROM posts p LEFT JOIN topics t ON p.topic_id = t.id WHERE p.post_number = 1 AND t.category_id = 12);")