mybatis条件构造器(一)

mybatis条件构造器(一)

1 准备工作

1.1 建表sql语句(Emp表)

SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;
-- ----------------------------
-- Table structure for emp
-- ----------------------------
DROP TABLE IF EXISTS `emp`;
CREATE TABLE `emp`  (`EMPNO` int NOT NULL AUTO_INCREMENT,`ENAME` varchar(10) CHARACTER SET utf8mb3 COLLATE utf8mb3_general_ci NULL DEFAULT NULL,`JOB` varchar(9) CHARACTER SET utf8mb3 COLLATE utf8mb3_general_ci NULL DEFAULT NULL,`MGR` double NULL DEFAULT NULL,`HIREDATE` date NULL DEFAULT NULL,`SAL` double NULL DEFAULT NULL,`COMM` double NULL DEFAULT NULL,`DEPTNO` int NULL DEFAULT NULL,PRIMARY KEY (`EMPNO`) USING BTREE,INDEX `DEPTNO`(`DEPTNO`) USING BTREE,CONSTRAINT `emp_ibfk_1` FOREIGN KEY (`DEPTNO`) REFERENCES `dept` (`DEPTNO`) ON DELETE RESTRICT ON UPDATE RESTRICT
) ENGINE = InnoDB AUTO_INCREMENT = 8899 CHARACTER SET = utf8mb3 COLLATE = utf8mb3_general_ci ROW_FORMAT = Dynamic;-- ----------------------------
-- Records of emp
-- ----------------------------
INSERT INTO `emp` VALUES (7369, '老张123', 'CLERK', 7902, '1980-12-30', 1200, 0, 20);
INSERT INTO `emp` VALUES (7499, 'ALLEN', 'SALESMAN', 7698, '1981-02-20', 1700, 300, 30);
INSERT INTO `emp` VALUES (7521, 'WARD', 'SALESMAN', 7698, '1981-02-22', 1250, 500, 30);
INSERT INTO `emp` VALUES (7566, 'JONES', 'MANAGER', 7839, '1981-04-02', 3975, NULL, 20);
INSERT INTO `emp` VALUES (7654, 'MARTIN', 'SALESMAN', 7698, '1981-09-28', 1250, 1400, 30);
INSERT INTO `emp` VALUES (7698, 'BLAKE', 'MANAGER', 7839, '1981-05-01', 2850, NULL, 30);
INSERT INTO `emp` VALUES (7782, 'CLARK', 'MANAGER', 7839, '1981-06-09', 2450, NULL, 10);
INSERT INTO `emp` VALUES (7788, 'SCOTT', 'ANALYST', 7566, '1987-07-13', 4000, NULL, 20);
INSERT INTO `emp` VALUES (7839, 'KING', 'PRESIDENT', NULL, '1981-11-17', 5000, NULL, 10);
INSERT INTO `emp` VALUES (7844, 'TURNER', 'SALESMAN', 7698, '1981-09-08', 1500, 0, 30);
INSERT INTO `emp` VALUES (7876, 'ADAMS', 'CLERK', 7788, '1987-07-13', 2100, NULL, 20);
INSERT INTO `emp` VALUES (7900, 'JAMES', 'CLERK', 7698, '1981-12-03', 950, NULL, 30);
INSERT INTO `emp` VALUES (7902, 'FORD', 'ANALYST', 7566, '1981-12-03', 4000, NULL, 20);
INSERT INTO `emp` VALUES (8896, '小明', 'MANAGER', 7698, '2023-01-02', 6666, 555, 10);
INSERT INTO `emp` VALUES (8897, '小红', 'SALESMAN', 7698, '2023-02-08', 5000, 1000, 10);
INSERT INTO `emp` VALUES (8898, 'zhang1', 'SALESMAN', 7698, '2023-01-31', 1243, 234, 10);
INSERT INTO `emp` VALUES (8899, '小小', 'SALESMAN', 7698, '2023-02-05', 123, 214, 10);
INSERT INTO `emp` VALUES (8900, '雄安', 'MANAGER', 7698, '2023-02-05', 13, 123, 10);SET FOREIGN_KEY_CHECKS = 1;

1.2 准备好测试环境

import com.zlz.ShiroStart2;
import org.springframework.boot.test.context.SpringBootTest;
@SpringBootTest(classes = ShiroStart2.class,webEnvironment = SpringBootTest.WebEnvironment.NONE)
public class DemoTest {}

2 多条件查询(全满足)

2.1 题目内容

查询员工姓名中包含a,薪水在1500-2000之间,津贴不为null的员工信息

2.2 对应的sql语句

SELECT EMPNO,ename,job,mgr,hiredate,sal,comm,deptno FROM emp WHERE (ename LIKE '%a%' AND sal BETWEEN 1500 AND 2000 AND comm IS NOT NULL)

2.3 示例代码

 @Testpublic void a(){//查询员工姓名中包含a,薪水在1500-2500之间,津贴不为null的员工信息//建议加上和实体类相同的泛型QueryWrapper<Emp> queryWrapper = new QueryWrapper<>();//queryWrapper是支持链式调用的,若没有指定条件,就用and拼接queryWrapper.like("ename","a").between("sal", 1500, 2000).isNotNull("comm");List<Emp> emps = empMapper.selectList(queryWrapper);emps.forEach(System.out::println);}

2.4 运行截图

2.4.1 实际执行的sql语句截图

2.4.2 数据显示截图

3 多排序字段查询

3.1 题目内容

#查询以部门编号升序,薪水降序的所有员工信息

3.2 对应的sql语句

SELECT EMPNO,ename,job,mgr,hiredate,sal,comm,deptno FROM emp ORDER BY deptno ASC,sal DESC

3.3 示例代码

 @Testpublic void a2(){/查询以部门编号升序,薪水降序的所有员工信息QueryWrapper<Emp> queryWrapper = new QueryWrapper<>();queryWrapper.orderByAsc("deptno").orderByDesc("sal");List<Emp> emps = empMapper.selectList(queryWrapper);emps.forEach(System.out::println);}

3.4 运行截图

3.4.1 实际执行的sql语句截图

3.4.2 数据显示截图

4 按照条件删除

4.1 题目内容

#删除员工姓名为小小且日志日期为2023-02-05的员工

4.2 对应的sql语句

DELETE FROM emp WHERE (ename = '小小' AND hiredate = '2023-02-05')

4.3 示例代码

//按照条件删除@Testpublic void a3(){//删除员工姓名为小小且日志日期为2023-02-05的员工QueryWrapper<Emp> queryWrapper = new QueryWrapper<>();queryWrapper.eq("ename", "小小").eq("hiredate", "2023-02-05");//获取受影响行数int result = empMapper.delete(queryWrapper);System.out.println("受影响行数: "+result);}

4.4 运行截图

4.4.1 实际执行的sql语句截图

4.4.2 数据显示截图

4.4.3 删除前数据库的数据

4.4.4 删除后数据库的数据