?

insert into Course values ('9-888','高等數學','831'); #---------------Teacher--添加信息---- insert into Teacher values ('804','李成','男','1958-09-01','副教授','計算機系'); insert into Teacher values ('856','張旭','男','1969-09-01','講師','電子工程系'); insert into Teacher values ('825','王萍','男','1972-09-01','助教','計算機系'); insert into Teacher values ('831','劉冰','男','1977-09-01','助教','電子工程系'); #--------------Score -- 添加信息--insert into Score values ('','103','3-245','86');insert into Score values ('','105','3-245','75');insert into Score values ('','109','3-245','68');insert into Score values ('','103','3-105','92');insert into Score values ('','105','3-105','88'); insert into Score values ('','109','3-105','76');insert into Score values ('','101','3-105','64');insert into Score values ('','107','3-105','91');insert into Score values ('','108','3-105','78');insert into Score values ('','101','6-166','85');insert into Score values ('','107','6-166','79');insert into Score values ('','108','6-166','81'); 練習題表 1、 查詢Student表中的所有記錄的Sname、Ssex和Class列。 2、 查詢教師所有的單位即不重復的Depart列。 3、 查詢Student表的所有記錄。 4、 查詢Score表中成績在60到80之間的所有記錄。 5、 查詢Score表中成績為85，86或88的記錄。 6、 查詢Student表中“95031”班或性別為“女”的同學記錄。 7、 以Class降序查詢Student表的所有記錄。 8、 以Cno升序、Degree降序查詢Score表的所有記錄。 9、 查詢“95031”班的學生人數。 10、?查詢Score表中的最高分的學生學號和課程號。（子查詢或者排序） 11、 查詢每門課的平均成績。 12、查詢Score表中至少有5名學生選修的并以3開頭的課程的平均分數。 13、查詢分數大于70，小于90的Sno列。 14、查詢所有學生的Sname、Cno和Degree列。 15、查詢所有學生的Sno、Cname和Degree列。 16、查詢所有學生的Sname、Cname和Degree列。 17、?查詢“95033”班學生的平均分。 18、 假設使用如下命令建立了一個grade表： create table grade(low int(3),upp int(3),rank char(1)) insert into grade values(90,100,’A’) insert into grade values(80,89,’B’) insert into grade values(70,79,’C’) insert into grade values(60,69,’D’) insert into grade values(0,59,’E’) 現查詢所有同學的Sno、Cno和rank列。 19、? 查詢選修“3-105”課程的成績高于“109”號同學成績的所有同學的記錄。 20、查詢score中選學多門課程的同學中分數為非最高分成績的記錄。 21、 查詢成績高于學號為“109”、課程號為“3-105”的成績的所有記錄。 22、查詢和學號為108的同學同年出生的所有學生的Sno、Sname和Sbirthday列。 23、查詢“張旭“教師任課的學生成績。 24、查詢選修某課程的同學人數多于5人的教師姓名。 25、查詢95033班和95031班全體學生的記錄。 26、? 查詢存在有85分以上成績的課程Cno. 27、查詢出“計算機系“教師所教課程的成績表。 28、查詢“計算 機系”與“電子工程系“不同職稱的教師的Tname和Prof。 29、查詢選修編號為“3-105“課程且成績至少高于選修編號為“3-245”的同學的Cno、Sno和Degree,并按Degree從高到低次序排序。 30、查詢選修編號為“3-105”且成績高于選修編號為“3-245”課程的同學的Cno、Sno和Degree. 31、?查詢所有教師和同學的name、sex和birthday. 32、查詢所有“女”教師和“女”同學的name、sex和birthday. 33、?查詢成績比該課程平均成績低的同學的成績表。 34、 查詢所有任課教師的Tname和Depart. 35?、 查詢所有未講課的教師的Tname和Depart. 36、查詢至少有2名男生的班號。 37、查詢Student表中不姓“王”的同學記錄。 38、查詢Student表中每個學生的姓名和年齡。 39、查詢Student表中最大和最小的Sbirthday日期值。 40、以班號和年齡從大到小的順序查詢Student表中的全部記錄。 41、查詢“男”教師及其所上的課程。 42、查詢最高分同學的Sno、Cno和Degree列。 43、查詢和“李軍”同性別的所有同學的Sname. 44、查詢和“李軍”同性別并同班的同學Sname. 45、查詢所有選修“計算機導論”課程的“男”同學的成績表。 查詢題目 26.select distinct cno from score where degree>85 27.select * from score where cno in(select cno from course where tno in(select tno from teacher where depart='計算機系'))28.select tname,prof from teacher where depart='計算機系' and prof not in(select prof from teacher where depart='電子工程系' )union select tname,prof from teacher where depart='電子工程系' and prof not in(select prof from teacher where depart='計算機系')29.select * from score where cno='3-105' and degree>any(select degree from score where cno='3-245')30.select * from score where cno='3-105' and degree>all(select degree from score where cno='3-245')31.select sname,ssex,sbirthday from student union select tname,tsex,tbirthday from teacher32.select sname,ssex,sbirthday from student where ssex='女' union select tname,tsex,tbirthday from teacher where tsex='女'33.select * from score a where degree<(select avg(degree) from score b where b.cno=a.cno )34.select tname,depart from teacher where tno in(select tno from course )35.select tname,depart from teacher where cno in(select tno from course where cno not in(select distinct cno from score))36.select class from student where ssex='男' group by class having count(*)>137.select * from student where sname not like '王%'38.select sname,year(now())-year(sbirthday) from student39.select max(sbirthday),min(sbirthday) from student40.select * from student order by class desc,sbirthday41.select tname,cname from course,teacher where course.tno=teacher.tno and teacher.tsex='男'42.select * from score where degree=(select max(degree) from score)select * from score order by degree desc limit 0,143.select sname from student where ssex=(select ssex from student where sname='李軍')44.select sname from student where ssex=(select ssex from student where sname='李軍') and class=(select class from student where sname='李軍')45.select * from score where cno=(select cno from course where cname='計算機導論') and sno in(select sno from student where ssex='男') 查詢 練習 26-45答案 1.select sname,ssex,class from student 2.select distinct depart from teacher 3.select * from student 4.select * from score where degree between 60 and 80 5.select * from score where degree in (85,86,88) 6.select * from student where class='95031' or ssex='女' 7.select * from student order by class desc 8.select * from score order by cno,degree desc 9.select count(*) from student where class='95031' 10.select sno,cno from score order by degree desc limit 0,1 select sno,cno from score where degree = (select max(degree) from score) 11.select avg(degree),cno from score group by cno 12.select avg(degree) from score where cno in(select cno from score group by cno having count(*)>4 ) and cno like '3%'select avg(degree) from score where cno like '3%' group by cno having count(*)>413.select sno from score where degree>70 and degree<9014.select sname,cno,degree from student,score where student.sno = score.sno15.select sno,cname,degree from course,score where course.cno = score.cno16.select sname,cname,degree from student,course,score where student.sno=score.sno and course.cno = score.cnoselect sname.cname.degree from student join score on student.sno=score.sno join course on course.cno=score.cno17.select avg(degree) from score where sno in(select sno from student where class='95033' )18.select sno,cno,rank from score,grade where degree between low and upp19.select * from score where cno='3-105' and degree>(select max(degree) from score where sno='109')select * from score where cno='3-105' and degree>(select max(degree) from score where sno='109' and cno='3-105')20.select * from score where sno in(select sno from score group by sno having count(*)>1) and degree<(select max(degree) from score where sno in(select sno from score group by sno having count(*)>1))select * from score a where sno in(select sno from score group by sno having count(*)>1) and degree<(select max(degree) from score b where b.cno = a.cno )21.select * from score where degree>(select degree from score where sno='109' and cno='3-105')22.select * from student year(sbirthday) = (select year(sbirthday) from student where sno='108')23.select * from score where cno in(select cno from course where tno = (select tno from teacher where tname='張旭'))24.select tname from teacher where tno=(select tno from course where cno = (select cno from score group by cno having count(*)>5))25.select * from student where class in('95033','95031') 答案 1-25

?

一. 總結

首先回顧： 連接查詢（幾張表連在一起 ?組成一個大表 在進行查詢 ---易忘） 子查詢 ? 聯合查詢 ? ?詳見 ?基礎篇

建表順序：首先 ?建主表 ?再建從表 ? 填寫內容也一樣 ?先填寫主表 在填寫 從表

?

?

小括號：

1. 小括號 可以表示 ? 獨立運算的部分 ?

2.帶小括號的是方法 ?（） ?比如 ?count（）； ?where ?尋找指定行：?

?

#---查詢95033班和95031班全體學生的記錄。select * from Student ,Course, Score where Student.Sno=Score.Sno and Course.Cno=Score.Cno and ( class='95033'or class='95031')

關鍵詞 : ?

?逗號 ??很重要； ??所有語句 ?幾乎都可以嵌套使用

?select.. from ??； where ??； group by ???having ?; ??order by ? ? ? ? union

distanct ? ?; or ???;in ?; ??and ??; ?not ? ? ? between ? ? ?<> ? any ?all ? ? ?(not is)

?

?

between ? ? ?<> [查看基礎篇 這里不做贅述]

1.not ?: ?not in ? 和 not like

in (not in） 【重要】

　　

#-----查詢選修某課程的同學人數多于5人的教師姓名。如果括號內的Cno 輸出值 不止一個 所以 必須 用 in 不能用= select Tname from Teacher where Tno=( select Tno from Course where Cno in (select Cno from Score group by Cno having count(*)>=5) )

　　

not like

?#- 查詢Student表中不姓“王”的同學記錄。 select * from Student where Sname not like'王%'?

2. group by ?和 ?where ?， count（*）連用的時候 注意 ?[帶小括號的表示方法}

首先定義：聚集函數：一種函數，它對一組行中的某個列執行計算，并返回單個值。1.where 和 having 簡單的講，where的條件是字段；而having 的條件可以是字段，也可以是聚集函數； 重要的是，where是篩選源數據，having多與group by 一起使用，并且條件常常是聚集函數；當有group by 時，having在group by 條件的后面，而where 在group by的前面。 聚集函數：sum，count，avg ...等等；2.count和sum count 是‘累計’； sum是‘累加’； 還是上面的表a_info中； 查詢每個年級中分數大于60的有多少人以及他們的平均分，總分是多少：3.sql語句的執行順序： （1）from 選取數據源； （2）where 篩選數據源； （3） group by 將篩選的數據源分組； （4）使用聚集函數計算； （5）having 篩選分組的數據； （6）計算表達式； （7）order by 排序； group where count（*）同時使用講解 #----查詢至少有2名男生的班號。select class from Student where Ssex='男' group by class having count(*)>=2

3.distanct： 使用方法 見 ?基礎部分 ?不做贅述

4.獲取時間 年月日 詳見 下一篇 ?博客 ? 以下簡略?

獲取的 為整數 可以進行大小比較：

獲取年 ?year（時間所在列名）----列名不加引號

獲取 當前時間 ?date(now())

獲取 天 ? ? ? ?date(時間所在的列)

#----查詢Student表中每個學生的姓名和年齡。 select Sname,year(now())-year(Sbrithday ) from Student#---查詢Student表中最大和最小的Sbirthday日期值。select Sname, max(date(sbrithday)) from Student unionselect Sname, min(date(sbrithday)) from Student#---以班號和年齡從大到小的順序查詢Student表中的全部記錄。 select * from Student order by class,year(Sbrithday);

?5.join on 鏈接三張表?

#------------ 查詢所有學生的Sname、Cname和Degree列。------------------------------select sname,cname,degree from student,course,score where student.sno=score.sno and course.cno = score.cno{正常做法}select sname，cname,degree from student join score on student.sno=score.sno join course on course.cno=score.cno{join on}

　　6. mysql 中常用的關鍵字

ADD ALL ALTER ANALYZE AND AS ASC ASENSITIVE BEFORE BETWEEN BIGINT BINARY BLOB BOTH BY CALL CASCADE CASE CHANGE CHAR CHARACTER CHECK COLLATE COLUMN CONDITION CONNECTION CONSTRAINT CONTINUE CONVERT CREATE CROSS CURRENT_DATE CURRENT_TIME CURRENT_TIMESTAMP CURRENT_USER CURSOR DATABASE DATABASES DAY_HOUR DAY_MICROSECOND DAY_MINUTE DAY_SECOND DEC DECIMAL DECLARE DEFAULT DELAYED DELETE DESC DESCRIBE DETERMINISTIC DISTINCT DISTINCTROW DIV DOUBLE DROP DUAL EACH ELSE ELSEIF ENCLOSED ESCAPED EXISTS EXIT EXPLAIN FALSE FETCH FLOAT FLOAT4 FLOAT8 FOR FORCE FOREIGN FROM FULLTEXT GOTO GRANT GROUP HAVING HIGH_PRIORITY HOUR_MICROSECOND HOUR_MINUTE HOUR_SECOND IF IGNORE IN INDEX INFILE INNER INOUT INSENSITIVE INSERT INT INT1 INT2 INT3 INT4 INT8 INTEGER INTERVAL INTO IS ITERATE JOIN KEY KEYS KILL LABEL LEADING LEAVE LEFT LIKE LIMIT LINEAR LINES LOAD LOCALTIME LOCALTIMESTAMP LOCK LONG LONGBLOB LONGTEXT LOOP LOW_PRIORITY MATCH MEDIUMBLOB MEDIUMINT MEDIUMTEXT MIDDLEINT MINUTE_MICROSECOND MINUTE_SECOND MOD MODIFIES NATURAL NOT NO_WRITE_TO_BINLOG NULL NUMERIC ON OPTIMIZE OPTION OPTIONALLY OR ORDER OUT OUTER OUTFILE PRECISION PRIMARY PROCEDURE PURGE RAID0 RANGE READ READS REAL REFERENCES REGEXP RELEASE RENAME REPEAT REPLACE REQUIRE RESTRICT RETURN REVOKE RIGHT RLIKE SCHEMA SCHEMAS SECOND_MICROSECOND SELECT SENSITIVE SEPARATOR SET SHOW SMALLINT SPATIAL SPECIFIC SQL SQLEXCEPTION SQLSTATE SQLWARNING SQL_BIG_RESULT SQL_CALC_FOUND_ROWS SQL_SMALL_RESULT SSL STARTING STRAIGHT_JOIN TABLE TERMINATED THEN TINYBLOB TINYINT TINYTEXT TO TRAILING TRIGGER TRUE UNDO UNION UNIQUE UNLOCK UNSIGNED UPDATE USAGE USE USING UTC_DATE UTC_TIME UTC_TIMESTAMP VALUES VARBINARY VARCHAR VARCHARACTER VARYING WHEN WHERE WHILE WITH WRITE X509 XOR YEAR_MONTH ZEROFILL mysql 關鍵字

?常用函數：

?

? ??

?

轉載于:https://www.cnblogs.com/ordinaryk/p/6134414.html

總結

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