Mybatis Plus 高级用法

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最新推荐文章于 2025-05-12 11:18:20 发布

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本文介绍了如何在MybatisPlus 3.0.7中使用LambdaQueryWrapper和链式查询，演示了复杂SQL的等价Lambda表达式和简化写法，包括LIKE操作、OR逻辑和NULL条件。

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1.lamda条件构造器的使用

要查询的sql :

SELECT * FROM `task_job` where title like '%倪欢测试%' and check_outside_pn_code >= 1;

LambdaQueryWrapper<TaskJob> lamda1 = new LambdaQueryWrapper<>();
LambdaQueryWrapper<TaskJob> lambda2 = new QueryWrapper<TaskJob>().lambda();
LambdaQueryWrapper<TaskJob> lambda3 = Wrappers.<TaskJob>lambdaQuery();

lamda1.like(TaskJob::getTitle, "倪欢测试").ge(TaskJob::getCheckOutsidePnCode, 1);
List<TaskJob> taskJobList = taskJobMapper.selectList(lamda1);
log.info("taskJobList:{}", taskJobList);

lambda2.like(TaskJob::getTitle, "倪欢测试").gt(TaskJob::getCheckOutsidePnCode, 1);
List<TaskJob> taskJobList1 = taskJobMapper.selectList(lambda2);
log.info("taskJobList1:{}", taskJobList1);

lambda3.like(TaskJob::getTitle, "倪欢测试").gt(TaskJob::getCheckOutsidePnCode, 1);
List<TaskJob> taskJobList2 = taskJobMapper.selectList(lambda3);
log.info("taskJobList2:{}", taskJobList2);

三者查询结果与sql 查询结果相同

要查询的sql :

SELECT * FROM `task_job` WHERE title LIKE '倪欢测试%' AND (check_outside_pn_code > 1 OR check_inside_user = NULL);

     LambdaQueryWrapper<TaskJob> lambda = Wrappers.<TaskJob>lambdaQuery();
        lambda.likeRight(TaskJob::getTitle, "倪欢测试").and
                (x -> x.gt(TaskJob::getCheckOutsidePnCode, 1).or().isNull(TaskJob::getCheckInsideUser));
        List<TaskJob> taskJobList = taskJobMapper.selectList(lambda);
        log.info("taskJobList:{}", taskJobList);

链式写法：mybatisPlus 3.0.7后的简化写法

SELECT * FROM `task_job` WHERE title LIKE '倪欢测试%' AND (check_outside_pn_code >= 1 OR check_inside_user = NULL);

        List<TaskJob> taskJobList = new LambdaQueryChainWrapper<TaskJob>(taskJobMapper).likeRight
                (TaskJob::getTitle, "倪欢测试").and(
                x -> x.gt(TaskJob::getCheckOutsidePnCode, 1).or().isNull(TaskJob::getCheckInsideUser)
        ).list();
        log.info("taskJobList:{}", taskJobList);