数据库简单操作

首先需要建立两张有关联的表，随便建了个课表和学生信息。

设置一个外键使两张表形成关联

下面是简单SQL语句的运用
查询

SELECT id,studentname FROM students;

筛选出不重复的课程

SELECT DISTINCT classID FROM students;

按某一顺序排列

SELECT studentname,age,studentID
FROM students
ORDER BY studentID;

在表中插入数据

INSERT INTO curriculum
VALUES (1006,"体育","彭老师");

搜索列中的指定模式

SELECT studentID
FROM students
WHERE studentID LIKE '%4';

搜索两表中相匹配的列

SELECT classID
FROM students
INNER JOIN curriculum
ON students.classID=curriculum.id

返回左表中所有的行 即使右表中没有匹配 没有匹配即显示为Null

SELECT studentname,classID
FROM students
LEFT JOIN curriculum
ON students.classID=curriculum.id

删除表中某数据

DELETE FROM students
WHERE id=7;

修改表中数据

UPDATE curriculum
SET classname='思修',teacher='周老师'
WHERE id='1002';