SQL农历转换函数（显示中文格式，加入润月的显示）

if object_id('fn_getlunar') is not null
    drop function fn_getlunar
go
create function dbo.fn_getlunar(@solarday datetime)
returns nvarchar(30)
as
begin
  declare @soldata int
  declare @offset int
  declare @ilunar int
  declare @i int
  declare @j int
  declare @ydays int
  declare @mdays int
  declare @mleap int
  declare @mleap1 int
  declare @mleapnum int
  declare @bleap smallint
  declare @temp int
  declare @year nvarchar(10)
  declare @month nvarchar(10)
  declare @day nvarchar(10)
  declare @chinesenum nvarchar(10)
  declare @outputdate nvarchar(30)
  set @offset=datediff(day,'1900-01-30',@solarday)
  --确定农历年开始
  set @i=1900
  --set @offset=@soldata
  while @i<2050 and @offset>0
  begin
    set @ydays=348
    set @mleapnum=0
    select @ilunar=dataint from solardata where yearid=@i      

    --传回农历年的总天数
    set @j=32768
    while @j>8
    begin
      if @ilunar & @j >0
        set @ydays=@ydays+1
      set @j=@j/2
    end
    --传回农历年闰哪个月 1-12 , 没闰传回 0
    set @mleap = @ilunar & 15
    --传回农历年闰月的天数 ,加在年的总天数上
    if @mleap > 0
    begin
      if @ilunar & 65536 > 0
        set @mleapnum=30
      else
        set @mleapnum=29
      set @ydays=@ydays+@mleapnum
    end
    set @offset=@offset-@ydays
    set @i=@i+1
  end
  if @offset <= 0
  begin
    set @offset=@offset+@ydays
    set @i=@i-1
  end
  --确定农历年结束
  set @year=@i
  --确定农历月开始
  set @i = 1
  select @ilunar=dataint from solardata where yearid=@year
  --判断那个月是润月
  set @mleap = @ilunar & 15
  set @bleap = 0
  while @i < 13 and @offset > 0
  begin
    --判断润月
    set @mdays=0
    if (@mleap > 0 and @i = (@mleap+1) and @bleap=0)
    begin--是润月
      set @i=@i-1
      set @bleap=1
      set @mleap1= @mleap
      --传回农历年闰月的天数
      if @ilunar & 65536 > 0
        set @mdays = 30
      else
        set @mdays = 29
    end
    else
    --不是润月
    begin
      set @j=1
      set @temp = 65536
      while @j<=@i
      begin
        set @temp=@temp/2
        set @j=@j+1
      end      

      if @ilunar & @temp > 0
        set @mdays = 30
      else
        set @mdays = 29
    end      

    --解除润月
    if @bleap=1 and @i= (@mleap+1)
      set @bleap=0    

    set @offset=@offset-@mdays
    set @i=@i+1
  end      

  if @offset <= 0
  begin
    set @offset=@offset+@mdays
    set @i=@i-1
  end      

  --确定农历月结束
  set @month=@i    

  --确定农历日结束
  set @day=ltrim(@offset)
  --输出日期
  set @chinesenum='0一二三四五六七八九十'
  while len(@year)>0
  select @outputdate=isnull(@outputdate,'')
         + substring(@chinesenum,left(@year,1)+1,1)
         , @year=stuff(@year,1,1,'')
  set @outputdate=@outputdate+'年'
         + case @mleap1 when @month then '润' else '' end
  if cast(@month as int)<10
    set @outputdate=@outputdate
         + case @month when 1 then '正'
             else substring(@chinesenum,left(@month,1)+1,1)
           end
  else if cast(@month as int)>=10
    set @outputdate=@outputdate
         + case @month when '' then '十' when 11 then '十一'
           else '十二' end
  set @outputdate=@outputdate + '月'
  if cast(@day as int)<10
    set @outputdate=@outputdate + '初'
         + substring(@chinesenum,left(@day,1)+1,1)
  else if @day between '' and ''
    set @outputdate=@outputdate
         + case @day when '' then '初十' else '十'+
           substring(@chinesenum,right(@day,1)+1,1) end
  else if @day between '' and ''
    set @outputdate=@outputdate
         + case @day when '' then '二十' else '廿' end
         + case @day when '' then '' else
           substring(@chinesenum,right(@day,1)+1,1) end
  else
    set @outputdate=@outputdate+'三十'
  return @outputdate
end
go
select dbo.fn_getlunar(getdate()) as [改编日期(农历)],getdate() as [改编日期(公历)]