Querydsl:如何按列进行左连接 [英] Querydsl: how to make left join by column

问题描述

我正在尝试在 querydsl 中匹配此 SQL 查询

Im trying to match this SQL query in querydsl

SELECT tr.* FROM test.TRIP_REQ tr left outer join test.ADDR_BOOK ab on tr.REQ_USERID=ab.USER_ID  

如果您加入身份列，我知道如何进行左连接查询，但很难使其与 2 个替代列的连接一起工作.tr.REQ_USERID 和 ab.USER_ID 不是标识列

I know how to make left join query if you join into identity column but struggle to make it work with joining on 2 alternative columns. tr.REQ_USERID and ab.USER_ID are not identity columns

这是我的 querydsl:

This is my querydsl:

QTripReq qTripReq = QTripReq.tripReq;
QAddressBook qABook = QAddressBook.addressBook;
JPAQuery query = new JPAQuery(entityManager);
query.from(qTripReq).leftJoin(qABook).on(qTripReq.requestorUser.id.eq(qABook.user.id)).list(qTripReq);

这会引发错误:

预期加入的路径！[select tripReq from com.TripReq tripReq left join ADDR_BOOK addressBook with tripReq.requestorUser.id = addressBook.user.id where tripReq.assignedCompany.id = ?1]

Path expected for join! [select tripReq from com.TripReq tripReq left join ADDR_BOOK addressBook with tripReq.requestorUser.id = addressBook.user.id where tripReq.assignedCompany.id = ?1]

推荐答案

需要在leftJoin()中添加目标实体路径，以便

You need to add a target entity path to leftJoin(), so that

QTripReq qTripReq = QTripReq.tripReq;
QAddressBook qABook = QAddressBook.addressBook;
JPAQuery query = new JPAQuery(entityManager);
query.from(qTripReq).leftJoin(qTripReq.addressBook, qABook).on(qTripReq.requestorUser.id.eq(qABook.user.id)).list(qTripReq);

查看使用连接文档中的部分.

这篇关于Querydsl:如何按列进行左连接的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！