QueryDSL select count() / count() 怎么样~？答案

【问题标题】：QueryDSL select count() / count() how~?QueryDSL select count() / count() 怎么样~？
【发布时间】：2020-08-24 04:48:15
【问题描述】：

选择

      (select count(*) from table2 where table2.table2Seq = table1.table1Seq) as count1,

      (select count(*) from table2 where table2.table2Seq = table1.table1Seq and table2Yn = true) as count2,

      (select count(*) from table2 where table2.table2Seq = table1.table1Seq) / (select count(*) from table2 where table2.table2Seq = table1.table1Seq and table2Yn = true) as count3

来自

      table1

按顺序

     count3

**我想要这个查询。你如何把它变成一个queryDSL？我想对子查询中的计数器除以子查询中的计数器进行排序。 **

NumberPath<Long> count1 = Expressions.numberPath(Long.class, “count1”);
NumberPath<Long> count2 = Expressions.numberPath(Long.class, “count2”);
NumberPath<Long> count3 = Expressions.numberPath(Long.class, “count3”);

JPQLQuery<OnlineTrainingCourseDto> query = getQuerydsl().createQuery()
    .select(
        new Dto(
            ExpressionUtils.as(
                JPAExpressions.select(table2.table2Seq.count())
                        .from(table2)
                        .where(table2.table2Seq.eq(table1.table1Seq)),
                count1
            ),
            ExpressionUtils.as(
                JPAExpressions.select(table2.table2Seq.count())
                        .from(table2)
                        .where(table2.table2Seq.eq(table1.table1Seq)
                        .and(table2.table2Yn.eq(true))),
                count2
            ),
            
            ***????? count1 / count2 as count3 ?????***

            )
        )
    )
    .from(table1)

【问题讨论】：

标签： querydsl

【解决方案1】：

您可以将表达式转换为数字表达式以访问除法运算符：

JPAExpressions.asNumber(
     JPAExpressions.select(table2.table2Seq.count())
                        .from(table2)
                        .where(table2.table2Seq.eq(table1.table1Seq)))
.divide(
    JPAExpressions.asNumber(JPAExpressions.select(table2.table2Seq.count())
                        .from(table2)
                        .where(table2.table2Seq.eq(table1.table1Seq)
                        .and(table2.table2Yn.eq(true))))
).as("count3")

【讨论】：

非常感谢。JPAExpressions.asNumber...我没想到。