如何使用查询DSL连接表

Question

我在应用程序中使用queryDsl进行复杂的搜索查询。我是querydsl的新手。我已经开始用下面的代码从一个表(TableA)中获取几行。但我必须在其他表(TableB)中找到具有相同id的person(Count)列表

public static Predicate find(final Long pId)
    QPerson qPerson = QPerson.person;
    Predicate predicate; 
    BooleanBuilder booleanBuilder = new BooleanBuilder();
    if (pId != null) {
        booleanBuilder.or(qPerson.person_no.eq(pId));
    } 
    if (name != null && !name.isEmpty()) {
        booleanBuilder.or(qPerson.expiry_dt.eq(name));
    }
    predicate = booleanBuilder.getValue();   
    return predicate;
    }

为多

:

pId         name
1001      sampleNameA
1002      sampleNameB
1003      sampleNameC

:表b

pId        name       interests
1001     sampleNameA    music   
1001     sampleNameA    dance
1001     sampleNameA    coding
1003     sampleNameC    music   
1002     sampleNameB    dance
1002     sampleNameB    coding

我需要得到这样的输出下面的查询

select cnt;* from master_person_table tableA，(select count(*) cnt from tableB WHERE pId = '1002'WHERE pId = '1002'

输出:

  count  pId        name       
    2    1002   sampleNameB    

我需要在我的HTML中显示行数(对于id=1002)

有没有人能帮我找到从表b中取出的pId的计数

Thanks in advance

Answer 1

请尝试以下查询:-

1。对于多个pid:-

SELECT COUNT(*) AS COUNT, pId, name FROM TableB GROUP BY pId

2。仅对于选定的pId:-

SELECT COUNT(*) AS COUNT, pId, name FROM TableB WHERE pId = 1002

如果你需要更多的帮助，请告诉我。