怎么在jooq做一笔钱

Question

你好我有一个方法来计算数据库中的值,我使用jooq然后迭代结果来进行求和,聚合一些字段.我的问题是我可以在jooq语句中执行所有操作,而不必遍历我的resultSet并手动添加它们吗？这是我到目前为止所做的:谢谢.

BigDecimal dealDiscountAmt = BigDecimal.ZERO;
BigDecimal standardAmtOneTimeTrue = BigDecimal.ZERO;
BigDecimal standardAmtOneTimeFalse = BigDecimal.ZERO;
BigDecimal oneTimeFalseX12 = BigDecimal.ZERO;

/** Dao for jooq access to db. */
@Resource(name = "dmDaoContext")
protected DSLContext dmDao_;


List<JDealMetricWorkflowCriteriaRecord> retValList = new ArrayList<JDealMetricWorkflowCriteriaRecord>();
JDealMetricWorkflowCriteriaRecord newDealRecord = new JDealMetricWorkflowCriteriaRecord();

List<JMetricServicePxvRecord> records = dmDao_.selectFrom(METRIC_SERVICE_PXV)
    .where(METRIC_SERVICE_PXV.DEAL_ID.eq(dealId), METRIC_SERVICE_PXV.PRODUCED_DATETIME.eq(whenProduced))
    .fetch();

for (JMetricServicePxvRecord record : records) {
  //sum all dealDiscounts
  dealDiscountAmt = dealDiscountAmt.add(record.getStandardTotalPxv().subtract(record.getProposedTotalPxv());

  if (record.getOneTime()) {
    //sum all dealDiscounts if oneTime is true
    standardAmtOneTimeTrue = standardAmtOneTimeTrue.add(record.getStandardTotalPxv().subtract(record.getProposedTotalPxv());
  } else {
    //sum all dealDiscounts if oneTime is false
    standardAmtOneTimeFalse = standardAmtOneTimeFalse.add(record.getStandardTotalPxv().subtract(record.getProposedTotalPxv());
  }
}

oneTimeFalseX12 = standardAmtOneTimeFalse.multiply(new BigDecimal("12"));

newDealRecord.setDealDiscount(dealDiscountAmt);
newDealRecord.setAnnualizedDealDiscount(standardAmtOneTimeTrue.add(oneTimeFalseX12));

retValList.add(newDealRecord);

Answer 1

jOOQ可以完成SQL可以执行的所有操作.

那么,让我们首先看看你想要运行的SQL查询

以下是在每个数据库上运行的标准SQL:

SELECT
  SUM(standard_total_pxv - proposed_total_pxv) 
    AS deal_discount,
  SUM(CASE WHEN one_time  = 1 THEN standard_total_pxv - propsed_total_pxv END) +
  SUM(CASE WHEN one_time != 1 THEN standard_total_pxv - propsed_total_pxv END) * 12 
    AS annualized_deal_discount
FROM metric_service_pxv
WHERE deal_id = :dealId AND produced_datetime = :whenProduced

我假设你的ONE_TIME专栏是一个NUMBER(1).如果您正在使用某种BOOLEAN类型(如果您的数据库支持该类型),那么您可以直接将该列用作谓词:

... WHEN one_time THEN ...

这个SUM(CASE ...)成语利用了SQL SUM()只聚合非NULL值的事实.因此,所有不需要的行都通过制作而从总和中移除NULL,具体取决于值ONE_TIME

现在用jOOQ:

// Assuming this static import
import static org.jooq.impl.DSL.*;

然后:

// Aliasing the table for brevity
MetricServicePxv m = METRIC_SERVICE_PXV.as("m");

// Reusing this sum several times:
AggregateFunction<BigDecimal> sum = sum(m.STANDARD_TOTAL_PXV.sub(m.PROPOSED_TOTAL_PXV));

// Here's your result:
Record2<BigDecimal, BigDecimal> result =
dmDao_
  .select(
    sum.as("DEAL_DISCOUNT"),
    sum.filterWhere(m.ONE_TIME.eq(1)).add(
    sum.filterWhere(m.ONE_TIME.ne(1)).mul(12)).as("ANNUALIZED_DEAL_DISCOUNT"))
  .from(m)
  .where(m.DEAL_ID.eq(dealId).and(m.PRODUCED_DATETIME.eq(whenProduced)))
  .fetchOne();

关于 FILTER (WHERE ...)

AggregateFunction.filterWhere()为简单起见,我在这里使用这个功能.SUM(...) FILTER (WHERE ...)是一种SQL标准语言功能,目前仅在PostgreSQL和HSQLDB中实现.在所有其他数据库中,SUM(CASE ...)生成聚合函数.