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  • MySQL查询示例

    use test;

    create table t1(
    tid smallint(5) unsigned auto_increment,
    tname varchar(50),
    tkecheng varchar(50),
    tgrade smallint(10),
    primary key(tid)
    )ENGINE=innodb default charset=utf8;

    INSERT into t1(tname,tkecheng,tgrade)
    values('xm','yuwen',76),
    ('xm','shuxue',89),
    ('xm1','yuwen',73),
    ('xm1','shuxue',84),
    ('xm2','yuwen',72),
    ('xm2','shuxue',88),
    ('xm3','yuwen',70),
    ('xm3','shuxue',69),
    ('xm4','yuwen',69),
    ('xm4','shuxue',79),
    ('xm5','yuwen',76),
    ('xm5','shuxue',78),
    ('xm6','yuwen',84),
    ('xm6','shuxue',83),
    ('xm7','yuwen',76),
    ('xm7','shuxue',68),
    ('xm8','yuwen',84),
    ('xm8','shuxue',78),
    ('xm9','yuwen',76),
    ('xm9','shuxue',98),
    ('xm10','yuwen',84),
    ('xm10','shuxue',78),
    ('xm11','yuwen',86),
    ('xm11','shuxue',68);
    commit;

    select * from t1;

    #1 数学成绩最高的前10条记录,按数学成绩降序排列

    select * from t1 where t1.tkecheng='shuxue' order by t1.tgrade desc limit 10;

    #2 查询所有科目都在80分以上记录
    select * from t1 where t1.tgrade>=80;

    s(sno,sn,sd,sa)sno,sn,sd,sa分别代表学号,学员姓名,班级,学员年龄
    c(cno,cn)cno,cn分别代表课程编号,课程名称
    sc(sno,cno,g)sno,cno,g分别代表学号,所选的课程编号,学习成绩

    create table s(
    sno smallint(5),
    sn varchar(50),
    sd varchar(50),
    sa smallint(10)
    )ENGINE=innodb default charset=utf8;


    insert into s(sno,sn,sd,sa)
    values(1001,'小明','班级1',24),
    (1002,'小赵','班级1',22),
    (1003,'小黄','班级2',23),
    (1004,'小张','班级2',25),
    (1005,'小李','班级3',23),
    (1006,'小罗','班级3',22),
    (1007,'小增','班级3',25);
    commit;

    create table c(
    cno smallint(5),
    cn varchar(50)
    )ENGINE=innodb default charset=utf8;

    insert into c(cno,cn)
    values(9001,'功能测试'),
    (9002,'自动化测试'),
    (9003,'性能测试'),
    (9004,'安全性测试'),
    (9005,'体验性测试'),
    (9006,'全栈测试');
    commit;

    create table sc(
    sno smallint(5),
    cno varchar(50),
    g varchar(50)
    )ENGINE=innodb default charset=utf8;


    insert into sc(sno,cno,g)
    values(1001,9001,78),
    (1001,9002,68),
    (1001,9003,84),
    (1001,9004,62),
    (1001,9005,98),
    (1001,9006,89),
    (1002,9001,68),
    (1002,9002,64),
    (1002,9003,83),
    (1002,9004,63),
    (1002,9005,90),
    (1003,9003,68),
    (1004,9004,99),
    (1005,9005,99),
    (1006,9001,69),
    (1006,9002,67),
    (1006,9003,86),
    (1006,9004,87),
    (1006,9005,90),
    (1006,9006,91),
    (1007,9001,99);
    commit;

    1)查询选修课程名称为‘性能测试’的学员学号和姓名?
    select s.sno,s.sn from s,sc,c
    where s.sno=sc.sno
    and sc.cno=c.cno
    and c.cn='性能测试';


    2)查询选修课程超过5门的学员学号和所属班级?
    select s.sno,s.sd from s
    where s.sno
    in (
    select sc.sno
    from c,sc
    where c.cno=sc.cno
    group by sc.sno
    having count(*)>5
    );


    3)用户名为xuelei在2013-09-16和2013-09-17天插入的任务。
    任务名包含"Arrow",文件大小大于200
    按文件由大到小排序,只提取出前5条数据

    create table User_task(
    Username varchar(50) comment '用户名',
    Taskid int comment '任务id',
    Taskname varchar(50) comment '任务名',
    Task_filesize int comment '文件大小',
    Insert_time datetime comment '插入日期'
    )ENGINE=innodb default charset=utf8;

    insert into User_task(Username,Taskid,Taskname,Task_filesize,Insert_time)
    values('xuelei',1001,'Arrow is not a ',200,str_to_date('2013-09-15 09:00:00', '%Y-%m-%d %H:%i:%S')),
    ('xuelei',1002,'hao Arrow is not b ',201,str_to_date('2013-09-16 09:00:01', '%Y-%m-%d %H:%i:%S')),
    ('xuelei',1003,'cc Arrow is not c ',203,str_to_date('2013-09-17 09:01:00', '%Y-%m-%d %H:%i:%S')),
    ('xuelei',1004,'ddArrow is not d ',204,str_to_date('2013-09-18 09:00:02', '%Y-%m-%d %H:%i:%S')),
    ('xuelei',1005,'efArrow is not e ',203,str_to_date('2013-09-19 09:20:00', '%Y-%m-%d %H:%i:%S')),
    ('ceshi',2001,'agbrrow is not a ',203,str_to_date('2013-09-16 09:10:00', '%Y-%m-%d %H:%i:%S')),
    ('ceshi',2002,'brrow is not b ',203,str_to_date('2013-09-16 16:20:00', '%Y-%m-%d %H:%i:%S')),
    ('ceshi',2003,'brrow is not c ',203,str_to_date('2013-09-15 09:20:00', '%Y-%m-%d %H:%i:%S')),
    ('xuelei',2002,'Afrrow is not b ',303,str_to_date('2013-09-16 16:20:00', '%Y-%m-%d %H:%i:%S')),
    ('xuelei',2003,'arrow is not c ',303,str_to_date('2013-09-16 09:20:00', '%Y-%m-%d %H:%i:%S')),
    ('xuelei',3001,'Acrrow is not a ',200,str_to_date('2013-09-15 09:00:00', '%Y-%m-%d %H:%i:%S')),
    ('xuelei',3002,'AArrow is not b ',201,str_to_date('2013-09-16 09:00:01', '%Y-%m-%d %H:%i:%S')),
    ('xuelei',3003,'aaArrow is not c ',203,str_to_date('2013-09-17 09:01:00', '%Y-%m-%d %H:%i:%S')),
    ('xuelei',3004,'Arrow is not d ',204,str_to_date('2013-09-18 09:00:02', '%Y-%m-%d %H:%i:%S')),
    ('xuelei',3005,'Acrrow is not e ',203,str_to_date('2013-09-19 09:20:00', '%Y-%m-%d %H:%i:%S')),
    ('ceshi',4001,'brrow is not a ',203,str_to_date('2013-09-20 09:10:00', '%Y-%m-%d %H:%i:%S')),
    ('ceshi',4003,'brrow is not c ',203,str_to_date('2013-09-22 09:20:00', '%Y-%m-%d %H:%i:%S')),
    ('xuelei',5002,'Arrow is not b ',303,str_to_date('2013-09-23 16:20:00', '%Y-%m-%d %H:%i:%S')),
    ('xuelei',5003,'arrow is not c ',303,str_to_date('2013-09-24 09:20:00', '%Y-%m-%d %H:%i:%S')),
    ('xuelei',1011,'Arrow is not c ',201,str_to_date('2013-09-19 09:00:00', '%Y-%m-%d %H:%i:%S')),
    ('xuelei',1008,'arrow is not a ',199,str_to_date('2013-09-15 09:00:00', '%Y-%m-%d %H:%i:%S')),
    ('xuelei',1009,'arrow is not b ',200,str_to_date('2013-09-15 09:00:00', '%Y-%m-%d %H:%i:%S')),
    ('xuelei',1010,'arrow is not c ',201,str_to_date('2013-09-15 09:00:00', '%Y-%m-%d %H:%i:%S')),
    ('xuelei',1012,'Arrow is not b ',201,str_to_date('2013-09-15 23:59:59', '%Y-%m-%d %H:%i:%S')),
    ('xuelei',1013,'Arrow is not c ',201,str_to_date('2013-09-17 23:59:59', '%Y-%m-%d %H:%i:%S'));-
    ('xuelei',1014,'what is a Arrow is not c ',202,str_to_date('2013-09-17 23:59:59', '%Y-%m-%d %H:%i:%S'));
    ('xuelei',1015,' Arrow Arrow Arrow',203,str_to_date('2013-09-17 23:59:59', '%Y-%m-%d %H:%i:%S'));
    commit;


    select * from User_task ut
    where ut.username='xuelei'
    and INSTR(ut.Taskname,binary 'Arrow')<>0
    and ut.task_filesize>200
    and date_format(ut.insert_time,'%Y-%m-%d') between '2013-09-16' and '2013-09-17'
    order by ut.task_filesize
    desc limit 5;

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  • 原文地址:https://www.cnblogs.com/NiceTime/p/8574064.html
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