sqlserver function

  1 -- Batch submitted through debugger: SQLQuery9.sql|15|0|C:\Users\Administrator\AppData\Local\Temp\~vs3AA0.sql
  2 -- =============================================
  3 -- Author:        <Author,,Name>
  4 -- Create date: <Create Date, ,>
  5 -- Description:    <Description, ,>
  6 -- =============================================
  7 ALTER FUNCTION to_char 
  8 (
  9     -- Add the parameters for the function here
 10     --<@Param1, sysname, @p1> <Data_Type_For_Param1, , int>
 11     @rule nvarchar(50)=‘‘,@datetime datetime
 12 )
 13 RETURNS nvarchar(50)
 14 AS
 15 BEGIN
 16 declare @v_rule nvarchar(50)
 17 declare @v_year nvarchar(4)
 18 declare @v_month nvarchar(2)
 19 declare @v_day nvarchar(2)
 20 declare @v_hour nvarchar(2)
 21 declare @v_min nvarchar(2)
 22 declare @v_sec nvarchar(2)
 23 
 24 if @datetime is null
 25 begin
 26     select @datetime=sysdatetime()
 27 end
 28 
 29 select @v_rule=Lower(@rule)
 30 select @v_year=DATEPART(YEAR,@datetime)
 31 select @v_month=DATEPART(month,@datetime)
 32 select @v_day=DATEPART(DAY,@datetime)
 33 select @v_hour=DATEPART(HOUR,@datetime)
 34 select @v_min=DATEPART(MINUTE,@datetime)
 35 select @v_sec=DATEPART(SECOND,@datetime)
 36 --‘yyyy-mm-dd‘
 37 declare @v_index int
 38 
 39 --解析年份规则
 40 select @v_index=CHARINDEX(‘yy‘,@v_rule,1)
 41 if @v_index <> 0
 42 begin
 43     select @v_index=CHARINDEX(‘yyyy‘,@v_rule,1)
 44     if @v_index = 0
 45     begin
 46         select @v_rule=REPLACE(@v_rule,‘yy‘,‘year‘);
 47         select @v_year=SUBSTRING(@v_year,3,2);--两位数表示‘-yy-‘
 48     end
 49     else
 50     begin
 51         select @v_rule=REPLACE(@v_rule,‘yyyy‘,‘year‘);--‘yyyy-‘
 52     end
 53 end
 54 
 55 --解析月份规则
 56 select @v_index=CHARINDEX(‘m‘,@v_rule,1)
 57 if @v_index <> 0 and SUBSTRING(@v_rule,@v_index,2)<>‘mi‘--判断非‘-mi-‘
 58 begin
 59     if CHARINDEX(‘mm‘,@v_rule,1)=0--一位数表示‘-m-‘
 60     begin
 61         select @v_index=CHARINDEX(‘m‘,@v_rule,1)
 62         --select @v_rule=REPLACE(@v_rule,‘m‘,‘month‘);--这里不能替换所有的m,因为m可能会替换掉后面的mi中的m
 63         set @v_rule=substring(@v_rule,1,@v_index-1)+‘month‘+substring(@v_rule,@v_index+1,len(@v_rule)-@v_index)
 64     end
 65     else
 66     begin
 67         select @v_rule=REPLACE(@v_rule,‘mm‘,‘month‘);--‘-mm-‘
 68         select @v_month=(case LEN(@v_month) when 1 then ‘0‘+@v_month else @v_month end)
 69     end
 70 end
 71 
 72 --解析日份规则
 73 if CHARINDEX(‘d‘,@v_rule)<>0
 74 begin
 75     if CHARINDEX(‘dd‘,@v_rule)=0
 76     begin
 77         set @v_rule=REPLACE(@v_rule,‘d‘,‘day‘)
 78         select @v_day=case LEN(@v_day) when 1 then ‘0‘+@v_day else @v_day end
 79     end
 80     else
 81     begin
 82         select @v_rule=replace(@v_rule,‘dd‘,‘day‘)
 83     end
 84 end
 85 
 86 --解析时分秒
 87 set @v_index = charindex(‘h‘,@v_rule,1)
 88 if @v_index>4 and substring(@v_rule,@v_index-4,5)=‘month‘
 89 begin
 90 set @v_index = charindex(‘h‘,@v_rule,@v_index+1)
 91 if @v_index<>0
 92     if charindex(‘hh‘,@v_rule,1)<>0
 93     begin
 94         set @v_rule=replace(@v_rule,‘hh‘,‘hour‘)
 95         set @v_hour= (case len(@v_hour) when 1 then ‘0‘+@v_hour else @v_hour end)
 96     end
 97     else
 98         set @v_rule=substring(@v_rule,1,@v_index-1)+‘hour‘+substring(@v_rule,@v_index+1,len(@v_rule)-@v_index)
 99 end
100 
101 if charindex(‘mi‘,@v_rule,1)<>0
102     set @v_rule=replace(@v_rule,‘mi‘,‘minute‘)
103 
104 if charindex(‘s‘,@v_rule,1)<>0
105     if charindex(‘ss‘,@v_rule,1)<>0
106     begin
107         set @v_rule=replace(@v_rule,‘ss‘,‘second‘)
108         set @v_sec=(case len(@v_sec) when 1 then ‘0‘+@v_sec else @v_sec end)
109     end
110     else
111         set @v_rule=replace(@v_rule,‘s‘,‘second‘)
112 
113 set @v_rule=REPLACE(@v_rule,‘year‘,@v_year)
114 set @v_rule=REPLACE(@v_rule,‘month‘,@v_month)
115 set @v_rule=REPLACE(@v_rule,‘day‘,@v_day)
116 set @v_rule=REPLACE(@v_rule,‘hour‘,@v_hour)
117 set @v_rule=REPLACE(@v_rule,‘minute‘,@v_min)
118 set @v_rule=REPLACE(@v_rule,‘second‘,@v_sec)
119 
120     -- Declare the return variable here
121     --DECLARE <@ResultVar, sysname, @Result> <Function_Data_Type, ,int>
122 
123     -- Add the T-SQL statements to compute the return value here
124     --SELECT <@ResultVar, sysname, @Result> = <@Param1, sysname, @p1>
125 
126     -- Return the result of the function
127     RETURN @v_rule
128 END