My new white , problem description, now have two MySQL database, each have the same structure of A table, two tables with the same data also have each other without the data, how to merge the two tables of data operation to heavy and there are two tables, merge requirements is given priority to with A table, table B if the records in the primary key in the table does not exist, it will add to the table A, if there is the reserved table A record of which eventually after merger, the results will also cover table B, to ensure that the two table data are complete and consistent, hope your bosses directions