#insert_conflict with empty update hash

insert_conflict_test.rb

require "sequel"

DB = Sequel.postgres("sequel_test")

DB.create_table? :items do
  primary_key :id
  String :name
  Float :price
end

update_payload = {} # imagine logic here that might result in empty hash

DB[:items]
  .insert_conflict(target: :id, update: update_payload)
  .insert(id: 1, name: "my item", price: 123.45)

output

/Users/madlep/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/sequel-4.46.0/lib/sequel/adapters/postgres.rb:195:in `async_exec': PG::SyntaxError: ERROR:  syntax error at or near "RETURNING" (Sequel::DatabaseError)
LINE 1: ... item', 123.45) ON CONFLICT ("id") DO UPDATE SET  RETURNING ...
                                                             ^
        from /Users/madlep/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/sequel-4.46.0/lib/sequel/adapters/postgres.rb:195:in `block in execute_query'
        from /Users/madlep/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/sequel-4.46.0/lib/sequel/database/logging.rb:45:in `log_connection_yield'
        from /Users/madlep/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/sequel-4.46.0/lib/sequel/adapters/postgres.rb:195:in `execute_query'
        from /Users/madlep/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/sequel-4.46.0/lib/sequel/adapters/postgres.rb:182:in `block in execute'
        from /Users/madlep/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/sequel-4.46.0/lib/sequel/adapters/postgres.rb:158:in `check_disconnect_errors'
        from /Users/madlep/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/sequel-4.46.0/lib/sequel/adapters/postgres.rb:182:in `execute'
        from /Users/madlep/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/sequel-4.46.0/lib/sequel/adapters/postgres.rb:535:in `_execute'
        from /Users/madlep/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/sequel-4.46.0/lib/sequel/adapters/postgres.rb:351:in `block (2 levels) in execute'
        from /Users/madlep/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/sequel-4.46.0/lib/sequel/adapters/postgres.rb:557:in `check_database_errors'
        from /Users/madlep/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/sequel-4.46.0/lib/sequel/adapters/postgres.rb:351:in `block in execute'
        from /Users/madlep/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/sequel-4.46.0/lib/sequel/database/connecting.rb:301:in `block in synchronize'
        from /Users/madlep/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/sequel-4.46.0/lib/sequel/connection_pool/threaded.rb:107:in `hold'
        from /Users/madlep/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/sequel-4.46.0/lib/sequel/database/connecting.rb:301:in `synchronize'
        from /Users/madlep/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/sequel-4.46.0/lib/sequel/adapters/postgres.rb:351:in `execute'
        from /Users/madlep/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/sequel-4.46.0/lib/sequel/dataset/actions.rb:1073:in `execute'
        from /Users/madlep/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/sequel-4.46.0/lib/sequel/adapters/postgres.rb:693:in `fetch_rows'
        from /Users/madlep/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/sequel-4.46.0/lib/sequel/dataset/actions.rb:1176:in `returning_fetch_rows'
        from /Users/madlep/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/sequel-4.46.0/lib/sequel/dataset/actions.rb:399:in `insert'
        from /Users/madlep/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/sequel-4.46.0/lib/sequel/adapters/shared/postgres.rb:1437:in `insert'
        from /Users/madlep/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/sequel-4.46.0/lib/sequel/adapters/shared/postgres.rb:1446:in `insert'
        from insert_conflict_test.rb:15:in `<main>'