这里首先将素材创建完毕,首先创建一个数据库并使用,这里我创建的数据库名为worker:
紧接着我们创建数据库表并创建表结构:
查看表结构:
接着我们导入数据:
这里我们可以看到素材已经创建完毕,这里我们进行之后的操作:
实现代码:
SELECT *
FROM worker;
实现代码:
SELECT DISTINCT 部门号
FROM worker;
实现代码:
SELECT COUNT(*) AS 职工人数
FROM worker;
实现代码:
SELECT MAX(工资) AS 最高工资,MIN(工资) AS 最低工资
FROM worker;
实现代码:
SELECT AVG(工资) AS '平均工资', SUM(工资) AS '总工资'
FROM worker;
实现代码:
CREATE TABLE 工作日期表 AS
SELECT 职工号, 姓名, 工作时间
FROM worker;
实现代码:
SELECT 2023 -YEAR(出生日期) AS 年龄
FROM worker;
实现代码:
SELECT 职工号, 姓名, 出生日期
FROM worker
WHERE 姓名 LIKE '刘%';
实现代码:
SELECT 姓名,工作时间
FROM worker
WHERE 出生日期 < '1960-01-01';
实现代码:
SELECT 姓名
FROM worker
WHERE 工资 BETWEEN 1000.00 AND 2000.00;
实现代码:
SELECT 姓名
FROM worker
WHERE 姓名 LIKE '陈%' OR 姓名 LIKE '李%';
实现代码:
SELECT 职工号, 姓名, CASE WHEN 政治面貌 = '党员' THEN '是' ELSE '否' END AS '党员'
FROM worker
WHERE 部门号 IN (102,103);
实现代码:
SELECT *
FROM worker
ORDER BY 出生日期;
实现代码:
SELECT 职工号, 姓名
FROM worker
ORDER BY 工资 DESC
LIMIT 3;
实现代码:
SELECT 部门号, COUNT(*) AS '党员人数'
FROM worker
WHERE 政治面貌 = '党员'
GROUP BY 部门号;
实现代码:
SELECT 部门号, SUM(工资) AS '总工资', AVG(工资) AS '平均工资'
FROM worker
GROUP BY 部门号;
实现代码:
SELECT 部门号, COUNT(*) AS '总人数'
FROM worker
GROUP BY 部门号
HAVING COUNT(*) > 4;
这里首先将素材创建完毕,首先创建一个数据库并使用,这里我创建的数据库名为worker,依旧使用上一个练习的数据库。
紧接着我们创建数据库表并创建表结构,查看表结构:
接着我们导入数据:
这里我们可以看到素材已经创建完毕,这里我们进行之后的操作:
实现代码:
SELECT *
FROM student;
实现代码:
SELECT *
FROM student
LIMIT 1,3;
实现代码:
SELECT id, name, department
FROM student;
实现代码:
SELECT *
FROM student
WHERE department IN ('计算机系', '英语系');
实现代码:
SELECT *
FROM student
WHERE YEAR(CURRENT_DATE) - birth
BETWEEN 18 AND 22;
实现代码:
SELECT department, COUNT(*) AS '人数'
FROM student
GROUP BY department;
实现代码:
SELECT c_name, MAX(grade) AS '最高分'
FROM score
GROUP BY c_name;
实现代码:
SELECT c_name, grade
FROM score
WHERE stu_id = (
SELECT id
FROM student
WHERE name = '李四'
);
实现代码:
SELECT student.id, student.name, student.department, score.c_name, score.grade
FROM student
JOIN score ON student.id = score.stu_id;
实现代码:
SELECT student.id, student.name, SUM(score.grade) AS '总成绩'
FROM student
JOIN score ON student.id = score.stu_id
GROUP BY student.id, student.name;
实现代码:
SELECT c_name, AVG(grade) AS '平均成绩'
FROM score
GROUP BY c_name;
实现代码:
SELECT student.*
FROM student
JOIN score ON student.id = score.stu_id
WHERE score.c_name = '计算机' AND score.grade < 95;
实现代码:
SELECT student.*
FROM student
WHERE id IN (
SELECT s1.stu_id
FROM score AS s1
JOIN score AS s2 ON s1.stu_id = s2.stu_id
WHERE s1.c_name = '计算机' AND s2.c_name = '英语'
);
实现代码:
SELECT student.name, score.c_name, score.grade
FROM student
JOIN score ON student.id = score.stu_id
WHERE score.c_name = '计算机'
ORDER BY score.grade DESC;
实现代码:
SELECT id FROM student
UNION
SELECT stu_id FROM score;
实现代码:
SELECT student.name, student.department, score.c_name, score.grade
FROM student
JOIN score ON student.id = score.stu_id
WHERE student.name LIKE '张%' OR student.name LIKE '王%';
实现代码:
SELECT student.name, YEAR(CURRENT_DATE) - student.birth AS '年龄', student.department, score.c_name, score.grade
FROM student
JOIN score ON student.id = score.stu_id
WHERE student.address LIKE '%湖南%';