Eclipselink扩展了JOIN子句 [英] Eclipselink extend JOIN clause

问题描述

当前代码：

CriteriaQuery criteriaQuery = cb.createQuery(MinutisPreke.class);
Root<MinutisPreke> from = criteriaQuery.from(MinutisPreke.class);
Join<LankomumasDiena, MinutisPreke> ld = from.join("lankomumasDiena", JoinType.LEFT);
cb.and(cb.equal(ld.get("intervalas"), 7));

生成以下查询：

SELECT COUNT(t0.pr_id) FROM preke AS t0 
LEFT OUTER JOIN lankomumas AS t1 
ON (t1.pr_id = t0.pr_id) 
WHERE (t1.intervalas = 7)

如何在LEFT OUTER JOIN中添加语句使用条件查询的 ON 子句，以便我的代码生成此查询：

How to add statement in the LEFT OUTER JOIN ON clause using criteria query so my code would generate this query:

SELECT COUNT(t0.pr_id) FROM preke AS t0 
LEFT OUTER JOIN lankomumas AS t1 
ON (t1.pr_id = t0.pr_id) AND (t1.intervalas = 7)

编辑1：
如果你没看到第一和第二个查询的任何差异，请阅读此主题：
SQL join：where子句与on子句

推荐答案

EclipseLink a如本文所述，在2.5夜间构建中支持ON子句：
https://bugs.eclipse.org/bugs/show_bug.cgi?id=367452
但它不是JPA规范的一部分，因此您需要将Join转换为EclipseLink的org.eclipse .persistence.internal.jpa.querydef.JoinImpl

EclipseLink added support for the ON clause in a 2.5 nightly build as described here: https://bugs.eclipse.org/bugs/show_bug.cgi?id=367452 but it is not a part of the JPA specification so you will need to cast the Join to EclipseLink's org.eclipse.persistence.internal.jpa.querydef.JoinImpl

((JoinImpl)ld).on(cb.and(cb.equal(ld.get("intervalas"), 7));

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