jpa多表查询及子查询

1. 主表1：1子表  主表查询

1.1 **主表 MasterEntity

    

@OneToOne
@JoinColumn(name = "masterext")
MasterExtendEntity masterExtendEntity; //关联表

**子表 MasterExtendEntity

1.2 查询

Root<MasterEntity> root

Path<String> code = root.join("MasterExtendEntity").get("ExtField1")

Iterator iterator =  query.codeList.iterator()
In invalue = cb.in(code);
while (iterator.hasNext()) {
    invalue.value(iterator.next())
}
searchList.add(invalue)

 

2. 主表1：1子表  子查询

 

2.1

**子表:MasterExtendEntity

@OneToOne
@JoinColumn(name = "MasterEntityId", nullable = false)
MasterEntity masterEntity

**主表 MasterEntity

 

2.2查询

//子查询
Subquery< MasterExtendEntity> subquery = query.subquery(MasterExtendEntity)
Root< MasterExtendEntity> extEntityRoot = subquery.from(MasterExtendEntity)
subquery.select(extEntityRoot)

Predicate correlatePredicate = cb.equal(extEntityRoot.get("MasterEntity"), root)
subquery.where(
        correlatePredicate,
        cb.equal(extEntityRoot.get("code"), String), cb.equal(extEntityRoot.get("code"), String)
)
searchList.add(cb.exists(subquery))