The old mysql table is deduplicated and the new table is imported with a new value of the primary key id.

The old mysql table is deduplicated and the new table is imported with a new value of the primary key id.

Business Requirements:
Table A has the id, n1, n2, and n3 fields to create an empty table,

Table B has fields such as id, n1, n2, n3, n4, and n5, which are old tables containing data,

The records in n1, n2, and n3 combinations in Table B are de-duplicated and then imported into Table A. The primary key of Table A must also be entered.

Solution:Deduplicate the records in Table B after query, and orchestrate the sequence number for the query results. Use the sequence number as the id value of the Table A to be inserted. The SQL statement is as follows:

Insert into a table (id, n1, n2, n3) select @ row: = @ row + 1 AS id, t1. * from (select distinct n1, n2, n3 from B table) t1, (select @ row: = 0) as t2