mysql語法大全

1、<p><b>　　MySQL語法大全</b></p><p>　　select * from emp; #注釋#---------------------------#----命令行連接MySql---------</p><p>　　#啟動mysql服務器net start mysql</p><p>　　#關閉 n

2、et stop mysql #進入mysql -h 主機地址 -u 用戶名 －p 用戶密碼 </p><p><b>　　#退出exit</b></p><p>　　#---------------------------#----MySql用戶管理---------</p><p>　　#修改密碼:首先在DOS 下進入mysql

3、安裝路徑的bin目錄下，然后鍵入以下命令:mysqladmin -uroot -p123 password 456;</p><p>　　#增加用戶#格式:grant 權限 on 數(shù)據(jù)庫.* to 用戶名@登錄主機 identified by '密碼'/*如，增加一個用戶user1密碼為password1，讓其可以在本機上登錄， 并對所有數(shù)據(jù)庫有查詢、插入、修改、刪除的權限。首先用以roo

4、t用戶連入mysql，然后鍵入以下命令： grant select,insert,update,delete on *.* to user1@localhost Identified by "password1"; 如果希望該用戶能夠在任何機器上登陸mysql，則將localhost改為"%"。 如果你不想user1有密碼，可以再打一個命令將密碼去掉。 grant select,inser

5、t,update,delete on mydb.* to user1@localhost identified by ""; */</p><p>　　grant all privileges on wpj1105.* to sunxiao@localhost identified by '123'; #all privileges 所有權限</p><

6、;p>　　#----------------------------#-----MySql數(shù)據(jù)庫操作基礎-----</p><p>　　#顯示數(shù)據(jù)庫show databases;</p><p>　　#判斷是否存在數(shù)據(jù)庫wpj1105,有的話先刪除drop database if exists wpj1105;</p><p>　　#創(chuàng)建數(shù)據(jù)庫crea

7、te database wpj1105;</p><p>　　#刪除數(shù)據(jù)庫drop database wpj1105;</p><p>　　#使用該數(shù)據(jù)庫use wpj1105;</p><p>　　#顯示數(shù)據(jù)庫中的表show tables;</p><p>　　#先判斷表是否存在,存在先刪除drop table if exists

8、student;</p><p>　　#創(chuàng)建表create table student(id int auto_increment primary key,name varchar(50),sex varchar(20),date varchar(50),content varchar(100))default charset=utf8;</p><p>　　#刪除表dro

9、p table student;</p><p>　　#查看表的結構describe student; #可以簡寫為desc student;</p><p>　　#插入數(shù)據(jù)insert into student values(null,'aa','男','1988-10-2','......');insert int

10、o student values(null,'bb','女','1889-03-6','......');insert into student values(null,'cc','男','1889-08-8','......');insert into student values(null,'d

11、d','女','1889-12-8','......');insert into student values(null,'ee','女','1889-09-6','......');insert into student values(null,'ff','null','1

12、889-09-6','......');#查詢表中的數(shù)據(jù)select * from student;select id,name from student;</p><p>　　#修改某一條數(shù)據(jù)update student set sex='男' where id=4;</p><p>　　#刪除數(shù)據(jù)delete from student

13、where id=5;</p><p>　　# and 且select * from student where date>'1988-1-2' and date<'1988-12-1';</p><p>　　# or 或select * from student where date<'1988-11-2' or da

14、te>'1988-12-1'; #betweenselect * from student where date between '1988-1-2' and '1988-12-1';</p><p>　　#in 查詢制定集合內(nèi)的數(shù)據(jù)select * from student where id in (1,3,5);</p><

15、p>　　#排序 asc 升序 desc 降序select * from student order by id asc;</p><p>　　#分組查詢 #聚合函數(shù) select max(id),name,sex from student group by sex;</p><p>　　select min(date) from student;</p><

16、p>　　select avg(id) as '求平均' from student;</p><p>　　select count(*) from student; #統(tǒng)計表中總數(shù)</p><p>　　select count(sex) from student; #統(tǒng)計表中性別總數(shù) 若有一條數(shù)據(jù)中sex為空的話,就不予以統(tǒng)計~</p><

17、p>　　select sum(id) from student;</p><p>　　#查詢第i條以后到第j條的數(shù)據(jù)(不包括第i條)select * from student limit 2,5; #顯示3-5條數(shù)據(jù)</p><p>　　#鞏固練習create table c( id int primary key auto_increment, name varchar(

18、10) not null, sex varchar(50) , #DEFAULT '男' , age int unsigned, #不能為負值(如為負值 則默認為0) sno int unique #不可重復);</p><p>　　drop table c;desc c;</p><p>　　insert into c (id,name,sex,age,

19、sno) values (null,'濤哥','男',68,1);insert into c (id,name,sex,age,sno) values (null,'aa','男',68,2);insert into c (id,name,sex,age,sno) values (null,'平平','男',35,3);...</

20、p><p>　　select * from c;</p><p>　　#修改數(shù)據(jù) update c set age=66 where id=2;update c set name='花花',age=21,sex='女' where id=2delete from c where age=21;</p><p>　　#常用查詢語句s

21、elect name,age ,id from cselect * from c where age>40 and age<60; #andselect * from c where age<40 or age<60; #orselect * from c where age between 40 and 60 #betweenselect * from c where age in (30,48,6

22、8,99); #in 查詢指定集合內(nèi)的數(shù)據(jù)select * from c order by age desc; #order by （asc升序 des降序）</p><p>　　#分組查詢select name,max(age) from c group by sex; #按性別分組查年齡最大值#聚合函數(shù)select min(age) from c;select avg(age)

23、as '平均年齡 ' from c;select count(*) from c; #統(tǒng)計表中數(shù)據(jù)總數(shù)select sum(age) from c;</p><p>　　#修改表的名字#格式:alter table tbl_name rename to new_namealter table c rename to a; #表結構修改create table test(id i

24、nt not null auto_increment primary key, #設定主鍵name varchar(20) not null default 'NoName', #設定默認值department_id int not null,position_id int not null,unique (department_id,position_id) #設定唯一值);</p><p

25、>　　#修改表的名字#格式:alter table tbl_name rename to new_namealter table test rename to test_rename;</p><p>　　#向表中增加一個字段(列)#格式:alter table tablename add columnname type;/alter table tablename add(columnname ty

26、pe);alter table test add columnname varchar(20);</p><p>　　#修改表中某個字段的名字alter table tablename change columnname newcolumnname type; #修改一個表的字段名alter table test change name uname varchar(50);</p><

27、;p>　　select * from test;</p><p>　　#表position 增加列testalter table position add(test char(10));#表position 修改列testalter table position modify test char(20) not null;#表position 修改列test 默認值alter table posi

28、tion alter test set default 'system';#表position 去掉test 默認值alter table position alter test drop default;#表position 去掉列testalter table position drop column test;#表depart_pos 刪除主鍵alter table depart_pos drop pr

29、imary key;#表depart_pos 增加主鍵alter table depart_pos add primary key PK_depart_pos(department_id,position_id);</p><p>　　#用文本方式將數(shù)據(jù)裝入數(shù)據(jù)庫表中（例如D:/mysql.txt）load data local infile "D:/mysql.txt" into t