sql语句带参数的模糊查询 （like @tag+'%')

"select PK_SIR_ID,FK_SI_ID,SIR_NAME,SIR_VALUE,SIR_TAG from souce_item_results  where  FK_SI_ID in " +

            " ( select PK_SI_ID from  souce_item where SI_UNIT_NUM= @iUnitNum and SI_CALCULATE_TIME=to_date(@CalculateTime,'yyyy-MM-dd') ) as SourceItem "+

            " and SIR_TAG like @tag+'%'"

SqlParameter[] parameters = {
     new SqlParameter("@iUnitNum", SqlDbType.Int,4),
     new SqlParameter("@CalculateTime", SqlDbType.Char,10),
     new SqlParameter("@tag", SqlDbType.VarChar,100),
                                        };

            parameters[0].Value = iUnitNum;
            parameters[1].Value = CalculateTime;
            parameters[2].Value = tag;