sql关联出每个月月初到月末的日期

创建方法：

create function fn_day_month(@year varchar(04),@month varchar(02))
returns @t table([date] datetime)
AS
begin
declare @begin datetime,@end datetime
select @begin=convert(datetime,@year+'-'+@month+'-01')
select @end=dateadd(day,-1,dateadd(month,1,@begin))

insert into @t select @begin

while @begin<@end
begin
insert into @t
select dateadd(day,1,@begin)

set @begin=dateadd(day,1,@begin)
end

return
end

测试：

select * from fn_day_month('2023','05')