Postgres ignore duplicate and delete code example

Example 1: query postgres delete duplicates

DELETE FROM dups a USING (
      SELECT MIN(ctid) as ctid, key
        FROM dups 
        GROUP BY key HAVING COUNT(*) > 1
      ) b
      WHERE a.key = b.key 
      AND a.ctid <> b.ctid

Example 2: To ignore duplicate keys during 'copy from' in postgresql

create temp table tmp_table on commit drop as select * from brand with no data;
copy tmp_table (name,slug) from '/var/lib/postgresql/data/Brands.csv' DELIMITER ',' csv header;
insert into brand select distinct on (slug) * from tmp_table;