Does dbDelta delete columns as well?

Question

I created a table using the dbDelta function and then removed a few columns and added a few. The new columns did get created but the old columns did not get deleted from the table.

Is there a different way I am supposed to delete columns from the table ?

Answer 1

As far as I know, dbDelta() is primarily used to add tables to the database. It can also add or alter columns. To delete columns, you should use $wpdb->query():

global $wpdb;
$table = $wpdb->prefix . 'table_name';
$wpdb->query( "ALTER TABLE $table DROP COLUMN column_name" );

Answer 2

No, dbDelta can add or alter columns, but not drop them.

The code for the dbDelta function is in wp-admin/includes/upgrade.php. You can examine what it is capable of there.