急求存储过程exec获得sql返回值，判断之后不走上一次循环

USE [nature]GO/****** Object:  StoredProcedure [dbo].[sc_yz]    Script Date: 07/16/2012 09:40:13 ******/SET ANSI_NULLS ONGOSET QUOTED_IDENTIFIER ONGOALTER PROCEDURE [dbo].[sc_yz]     @fun_table_name as varchar(5000),    --参数    @bl int output, --数据使用量    @b_m_return varchar(100) output --返回表名ASBEGINdeclare @bm  varchar(300),--表名@m  int,--循环1@n  int, --循环1@a  int,--循环2@b  int, --循环2@tj varchar(300),--条件@linshi varchar(300), --临时@sql nvarchar(4000),  --sql@b_m_l_s varchar(300) --临时表名set  @m=CHARINDEX(';',@fun_table_name)  set  @n=1   WHILE  @m>0      BEGIN          set  @bm=substring(@fun_table_name,@n,@[email protected])          set  @[email protected]+1          set  @m=CHARINDEX(';',@fun_table_name,@n)         set  @a=CHARINDEX(',',@bm)          set  @b=1          WHILE  @a>0              BEGIN                set  @linshi=substring(@bm,@b,@[email protected])                  if @b=1                    begin                    set @sql='select @bl = count(*) from [email protected]                    set @b_m_l_s = @linshi                    end                else                    begin                    set @sql+=' [email protected]                    end                exec sp_executesql @sql,[email protected] int Output ',@bl Output                if(@bl>=1)                begin                set @b_m_return = @b_m_l_s                end                else                begin                set @b_m_return = ''                end                set  @[email protected]+1                  set  @a=CHARINDEX(',',@bm,@b)                print @sql            END    ENDEND