instance method fetch_table_collations

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 757
        def fetch_table_collations(tables)
          fetch_by_schema(tables) do |schema, group|
            by_name = query_all(<<~SQL).to_h { |row| [row["table"], row["collation"]] }
              SELECT table_name AS 'table', table_collation AS 'collation'
              FROM information_schema.tables
              WHERE table_schema = #{schema}
                AND table_name IN (#{quoted_table_names(group)})
            SQL

            group.index_with { |table| by_name[bare_table_name(table)] }
          end
        end