存储过程如何根据不同选择执行不同的查询条件，例如选择字段为A，执行一段查询条件，为B，执行另一段查询条件

ALTER  proc [dbo].[usp_user]

    @produceline  varchar(10),

    @workproc  varchar(20),

    @finishid   varchar(30),

    @auitdate  datetime,

    @abtype  varchar(10)

as

declare @sql varchar(1000)

begin

    set @sql='select SUM(RpTotalNums) as 投料数 from [BMMES_JM].[dbo].[M_JOB_REPORTWORK] where '

        + 'RpProduceLine = ' + cast(@produceline as varchar)

        + 'AND RpWorkproc = ' + cast(@workproc as varchar)

        + 'AND RpFinishID = ' + cast(@finishid as varchar)

        + 'AND RpAuditStatus = 1 and RpAuditDate between convert(varchar(10),DATEADD(dd,0,'+cast(@auitdate as varchar)+'),120)+07:00 and convert(varchar(10),DATEADD(dd,1,'+cast(@auitdate as varchar)+'),120)+07:00 '

    if (@abtype= 'A')

        begin

            set @sql=@sql+' and RpABMaterial = ''A'' and CHARINDEX(''_'',RpERPWorkOrder)=0 '

        end

    else if (@abtype= 'B')

        begin

            set @sql=@sql+' and RpABMaterial = ''B'' '

        end

    else if (@abtype= '返花')

        begin

            set @sql=@sql+' and CHARINDEX(''_'',RpERPWorkOrder)>0 and RpABMaterial = ''A'' '

        end

    else 

        begin 

            set @sql=@sql+' and RpAuditStatus = 1 '

        end

    exec (@sql)

end