EXISTS (select 1 from ... ) JOIN 查询(包括INNER JOINm, LEFT JOIN, RIGHT JOIN) select ... from table1 a join table2 b on a.xxx = b.xxx where ...; select ... from table1 a left join table2 b on a.xxx = b.xxx where ...; select ... from table1 a right join table2 ...
### SQL: select tmpifro.* from (SELECT MAX(nvl(ifm.opportunity_id,'')) AS opportunity_name, MAX(nvl(IFM.restricted, '')) AS restricted, MAX(nvl(ifc.client_id, '')) AS client_id, MAX(nvl(ifc.disp_name, '')) AS client_name, MAX(nvl(ifc.disp_alt_name, '')) AS client_alt...
SELECT 1 FROM user test-while-idle: true test-on-borrow: true test-on-return: false # 是否缓存preparedStatement,也就是PSCache 官方建议MySQL下建议关闭 个人建议如果想用SQL防火墙 建议打开 pool-prepared-statements: true max-pool-prepared-statement-per-connection-size: 20 # 配置监控统计拦截的filters...
public <E> List<E> query(MappedStatement ms, Object parameterObject, RowBounds rowBounds, ResultHandler resultHandler) throws SQLException { //创建缓存Key BoundSql boundSql = ms.getBoundSql(parameterObject); //key = -575461213:-771016147:mapper.UserMapper.getUserById:0:2147483647:select * from te...
* select * from order WHERE id=1;//得到user_id * select * from user WHERE id=1 //1 是上一个查询得到的user_id的值 * @param userID * @return *///根据订单ID得到订单信息(包含user_id)publicOrdersgetOrderByOrderId(int orderId);//根据用户ID查询用户信息publicUsergetUserByUserId(int use...
1、单个参数 单个参数的传参比较简单,可以是任意形式的,比如#{a} 、#{b} 或者#{param1} ,但是为了开发规范,尽量使用和入参时一样。 Mapper如下: UserInfo selectByUserId(String userId); XML如下: <select id="selectByUserId" resultType="cn.cb.demo.domain.UserInfo">select* from user_info where ...
select * from t_user </select> </mapper> 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 测试:SelectMapperTest @Test public void testGetUserById(){ SqlSession sqlSession = SqlSessionUtil.getSqlSession(); SelectMapper mapper = sqlSession.getMapper(SelectMapper.class); ...
- 1、定义SQL --> <mapper namespace="dao"> <select id="selectAll" resultType="user"> select * from t_user </select> </mapper> //2、执行SQL sqlSession.select("dao.selectAll"); 很,以上这个 SQL ,在编译阶段我们都已经知道它的主体结构,即查询 t_user 表的所有记录,而无需等到程序运行...
select*from ${tableName}where name=${name} 如果传入的参数tableName为user; delete user; --,那么sql动态解析之后,预编译之前的sql将变为: 代码语言:javascript 复制 select*from user;deleteuser;--where name=?; --之后的语句将作为注释不起作用,顿时我和我的小伙伴惊呆了!!!看到没,本来的查询语句,竟然...
1. 概述 1.1 什么是Mybatis? 1.2 Mybatis 操作数据库的方式 1.3 Mybatis 操作数据库的七大步骤? 1.4 Mybatis 的开发优点 2. Mybatis 操作数据库具体实现 2.1 创建一个数据库表 2.2 创建一个maven项目,配置pom.xml文件,导入相关依赖 2.3 创建mybatis 核心配置文件 ...