一.基础查询

将使用以下sql文件的数据

sql文件地址 https://gitee.com/newstarless/CrackJetBrainsFile/blob/master/school1.sql

1.简单查询student表的sno,sname,ssex,sbirth字段

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SELECT sno,sname,ssex,sbirth from student;

2.将查询student表的ssex的0代表女，1代表男显示

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SELECT 
    sno, 
    sname, 
    CASE 
        WHEN ssex = 1 THEN '男'
        WHEN ssex = 0 THEN '女'
        ELSE '未知'
    END AS ssex,
    sbirth 
FROM 
    student;

3.将查询student表的sbirth判断一些若为null则显示为 无,不然正常显示

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SELECT 
    sno, 
    sname, 
    ssex, 
    CASE 
        WHEN sbirth IS NULL THEN '无'
        ELSE sbirth
    END AS sbirth 
FROM 
    student;

4.将查询student表的sbirth按升序排序

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SELECT sno,sname,ssex,sbirth from student order by sbirth;

5.将查询student表的sbirth按降序排序

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SELECT sno,sname,ssex,sbirth from student order by sbirth desc;

6.模糊查询student表的姓张的

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SELECT sno,sname,ssex,sbirth from student WHERE sname like '张%';

7.完整语法查询格式

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SELECT 目标字段 | 字段表达式或函数
FROM 数据源
[WHERE <元组选择条件>]
[GROUP BY <分组字段>] [HAVING <组选择条件>]
[ORDER BY <排序字段> [ASC | DESC]]

ASC为升序,DESC 为降序

二.多表查询

完善中….