I have 2 sets of 2 tables with identical columns, set up some 15 years ago:

alt_subjects
alt_posts

board_subjects
board_posts

There's an ID column in alt_subjects that corresponds to alt_posts, and in board_subjects that corresponds to board_posts.

I realized a long time ago that it would have been better to have alt_posts and board_posts in one table, then alt_subjects and alt_posts in a table with a column for "category" or something. But I've been procrastinating because it's a daunting task :-/

The best I can figure is to:

A. add a column to alt_subjects called "new_ID"

Then write a PHP script that will:

1. Select all of the alt_subjects and store it in an array

2. Read the last ID in board_subjects, then in a loop modify the alt_subjects array to reassigns a new ID to each row, and create an associative array to link the original ID to the new ID

3. Insert the updated alt_subjects array into board_subjects

4. Update alt_subjects with the new ID in the "new_ID" column

5. Select all of the alt_posts and store it in an array

6. Update the array with the new ID from the associative array in #2

7. Insert the update alt_posts array into board_posts

8. Modify my public script so that if the user is looking at what was once alt_subjects and the ID is less than the last ID at the time of the merge, select the new ID from alt_subjects and re-select from board_subjects

That feels like a long and tedious process! Before I jump in head first, is there an easier way?