Just a simple copy record function.
First of all, pick a random temporary table name, and ensure you don’t have a table in your database by that name.
Then, copy the record you want to copy, from the source table, into a temp table:
CREATE TEMPORARY TABLE <temp_table> SELECT * FROM <source_table> WHERE <source_table_id_field> = <id_to_copy>;
Because we want the new record to have a new ID number, lets drop that field from the temporary table:
ALTER TABLE <temp_table> DROP <source_table_id_field>;
Now we just copy it back in, but because we are one field short (the ID one) then we just pass a zero instead and let MySQL go and get a new ID from the auto increment engine.:
INSERT INTO <source_table> SELECT 0, <temp_table>.* FROM <temp_table>;
Job done. Just need to tidy up and drop the temporary table (careful you delete the right one)
DROP TABLE <temp_table>;
PS. This will only work if your auto increment ID field is the first field in the table (which is generally the case for every database table I have ever worked with)