解读@SelectProvider的使用方法

@SelectProvider(type = SalesOrderProvider.class, method = "selectSalesInformation")
    List<SalesInformation> selectSalesInformation(@Param("createDateStart") String createDateStart, @Param("createDateEnd") String createDateEnd);

public String selectSalesInformation(@Param("createDateStart") String createDateStart, @Param("createDateEnd") String createDateEnd){
        StringBuffer sql = new StringBuffer();
        sql.append(" SELECT ORDER_STATUS,b.number,b.unit_price,a.CREATE_DATE FROM hl4pl_sales_order a join hl4pl_sales_order_goods b ");
        sql.append(" where a.ID=b.ID and a.CREATE_DATE BETWEEN #{createDateStart} and #{createDateEnd} ");
        sql.append(" HAVING ORDER_STATUS =8 or ORDER_STATUS =6 ");
        return sql.toString();
    }

public SalesInformaitonVo getSalesInformation(String createDateStart, String createDateEnd){
        List<SalesInformation> salesInformations = salesOrderMapper.selectSalesInformation(createDateStart,createDateEnd);
        BigDecimal salesVolume = BigDecimal.ZERO;//销售额
        BigDecimal totalOrders = BigDecimal.ZERO;//订单总量
        int totalSales = salesInformations.size();//销售总量
        for (SalesInformation salesInformation : salesInformations) {
            if (salesInformation.getNumber()!=null&&salesInformation.getUnitPrice()!=null&&salesInformation.getNumber()!=BigDecimal.ZERO&&salesInformation.getUnitPrice()!=BigDecimal.ZERO){
                salesVolume = salesVolume.add(salesInformation.getNumber().multiply(salesInformation.getUnitPrice()));
                totalOrders = totalOrders.add(salesInformation.getNumber());
            }
        }
        SalesInformaitonVo salesInformaitonVo = new SalesInformaitonVo();
        salesVolume=salesVolume.divide(BigDecimal.valueOf(10000));
        BigDecimal bigDecimal = salesVolume.setScale(2, BigDecimal.ROUND_UP);//四舍五入两位小数
        salesInformaitonVo.setSalesVolume(bigDecimal);
        salesInformaitonVo.setTotalOrders(totalOrders);
        salesInformaitonVo.setTotalSales(totalSales);
        return salesInformaitonVo;
    }

@Select({"<script>",
    "SELECT * FROM tbl_order",
    "WHERE 1=1",
    "<when test='title!=null'>",
    "AND mydate = #{mydate}",
    "</when>",
    "</script>"})
List<ExpendVo> queryExpend(ExpendDto dto);