Remove duplicates in large MySql table

Question

I have a question about MySql. I have a table with 7.479.194 records. Some records are duplicated. I would like to do this:

insert into new_table 
  select *         


        

Answer 1

This will populate NEW_TABLE with unique values, and the id value is the first id of the bunch:

INSERT INTO NEW_TABLE
  SELECT MIN(ot.id),
         ot.city,
         ot.post_code,
         ot.short_ccode
    FROM OLD_TABLE ot
GROUP BY ot.city, ot.post_code, ot.short_ccode

If you want the highest id value per bunch:

INSERT INTO NEW_TABLE
  SELECT MAX(ot.id),
         ot.city,
         ot.post_code,
         ot.short_ccode
    FROM OLD_TABLE ot
GROUP BY ot.city, ot.post_code, ot.short_ccode