What does the MySQL error message "Table already in use by the statement that called this stored function/trigger" mean?

edit

This error message usually occurs when a stored procedure or trigger is trying to access a table that is already being used by the same stored procedure or trigger. This can happen when the same table is being accessed recursively by the same procedure or trigger. To resolve this issue, you can either modify the code to prevent the recursion or use a different table for the next operation.