树形数据编号重排的通用存储过程

--重排编码的存储过程
CREATE PROC p_RTaxisCode
@TableName sysname,    --重排编码的表名
@FieldName sysname,    --编码字段名
@CodeRule varchar(100)  --以逗号分隔的编码规则,每层编码的长度,比如1,2,3,表示有三层编码,第一层长度为1,第二层长度为2,第三层长度为3
AS
--参数检查
IF ISNULL(OBJECTPROPERTY(OBJECT_ID(@TableName),N'IsUserTable'),0)=0
BEGIN
 RAISERROR(N'"%s"不存在,或者不是用户表',1,16,@TableName)
 RETURN
END
IF NOT EXISTS(SELECT * FROM SYSCOLUMNS WHERE ID=OBJECT_ID(@TableName) AND name=@FieldName)
BEGIN
 RAISERROR(N'列名"%s"在用户表"%s"中无效',1,16,@FieldName,@TableName)
 RETURN 
END
IF ISNULL(@CodeRule,'')=''
BEGIN
 RAISERROR(N'必须编码规则字符串',1,16)
 RETURN 
END
IF PATINDEX(N'%[^0-9^,]%',@CodeRule)>0
BEGIN
 RAISERROR(N'编码规则字符串"%s"中只能包含数字和逗号(,)',1,16,@CodeRule)
 RETURN 
END

--生成编码重排处理语句
DECLARE @s nvarchar(4000),@len int,@lens int
SELECT
 @TableName=QUOTENAME(@TableName),
 @FieldName=QUOTENAME(@FieldName),
 @len=LEFT(@CodeRule,CHARINDEX(N',',@CodeRule+N',')-1),
 @lens=@len,
 @CodeRule=STUFF(@CodeRule,1,CHARINDEX(N',',@CodeRule+N','),N'')+N',',
 @s=N'RIGHT('+CAST(POWER(10,@len) as varchar)
  +N'+(SELECT COUNT(DISTINCT '+@FieldName
  +N') FROM '+@TableName
  +N' WHERE '+@FieldName+N'<=a.'+@FieldName
  +N' AND LEN('+@FieldName+N')='+CAST(@len as varchar)
  +N'),'+CAST(@len as varchar)+N')'

WHILE LEN(@CodeRule)>1
BEGIN
 SELECT
  @len=LEFT(@CodeRule,CHARINDEX(N',',@CodeRule)-1),
  @s=@s
   +N'+CASE WHEN LEN('+@FieldName
   +N')>'+CAST(@lens as varchar)
   +N' THEN RIGHT('+CAST(POWER(10,@len) as varchar)
   +N'+(SELECT COUNT(DISTINCT '+@FieldName
   +N') FROM '+@TableName
   +N' WHERE '+@FieldName+N'<=a.'+@FieldName
   +N' AND '+@FieldName+N' LIKE LEFT(a.'+@FieldName
   +N','+CAST(@lens as varchar)
   +N')+'''+REPLICATE(N'_',@len)
   +N'''),'+CAST(@len as varchar)
   +N') ELSE '''' END',
  @lens=@lens+@len,
  @CodeRule=STUFF(@CodeRule,1,CHARINDEX(N',',@CodeRule),N'')
END
EXEC(N'UPDATE a SET '+@FieldName+N'='+@s+N' FROM '+@TableName+N' a')