Конкатенация числового значения Int и строки в mysql

Пример конкатенации с приведением типа.

update limit_year set limit_year.end_date = concat(cast(limit_year.year_number+1 as char),'.01.01') ,
 limit_year.start_date = concat(cast(limit_year.year_number as char),'.01.01')
 where limit_year.start_date is null and limit_year.end_date is null;

Пример простой конкатенации значений int и varchar.

update limit_year set limit_year.end_date = concat(limit_year.year_number+1,'.01.01') ,
 limit_year.start_date = concat(limit_year.year_number,'.01.01')
 where limit_year.start_date is null and limit_year.end_date is null;