• Restore database via terminal.

psql -U username -d dbname < filename.sql

• Identity Column

  Staying with a "serial"

  We need to create a sequence and sync it with the highest value in the column.

  create sequence the_table_id_seq;
  select setval('the_table_id_seq', max(id))
  from the_table;
  
  

  Then use this for the default and link the sequence to the column.

  alter table the_table
    alter id set not null,
    alter id set default nextval('the_table_id_seq') ;
  
  alter sequence the_table_id_seq owned by the_table.id;
  
  

  Using an identity column (recommended)

  To make this a proper (recommended) identity column (Postgres 10 and later) you can do it like this:

  alter table the_table
    alter id set not null,
    alter id add generated always as identity;
  
  

  Now adding the identity attribute created a new sequence which we need to sync with the existing values in the column:

  Date convert

  TO_DATE(STRING, 'DDMMYYYY')
  
  TO_CHAR(STRING, 'DD-MM-YYYY') - For string - date conversion
  

  Row to column

  string_agg(name::text, ',')services