sql數(shù)據(jù)庫(kù)基本語(yǔ)句

1、123456789 STUcreate table STU(SNO varchar(7) primary key,SNAME varchar(8),SCLASS 123456789 STUcreate table STU(SNO varchar(7) primary key,SNAME varchar(8),SCLASS AD添加列alter table STU add alter table STU add SSEX L(專(zhuān)業(yè))table L.SPENAME from L SQL查詢語(yǔ)1.2.查詢學(xué)SNO,SNAME from distinct用于除去重復(fù)為19select * frm ST

2、U where where 可用于輸入查詢的條件限制,SQL關(guān)系運(yùn)算符有4.查為18的男學(xué)生學(xué)號(hào)select SNO,SNAME from STU where SSEX=男 and -and,or,not是SQL的邏輯運(yùn)算5.查在1820select * from STUand,or,not是SQL的邏輯運(yùn)算5.查在1820select * from STU where SAGE=18 select * from STU where SAGE bet an表范圍,對(duì)應(yīng)的否定為18 and 20; 查詢專(zhuān)業(yè)為01,02select * from STU where SPENO=01 or 6.1

3、select* from STU where SPENO in01,02); in 表示查詢的集合,否定使用 not in7.查詢所有姓陳的學(xué)生信select *from STU where SNAME like陳%; ps:名字中帶有陳應(yīng)該寫(xiě)為: SNAME like %陳%字符匹配:%匹配任意個(gè)任意字符,_8.select * frm STU is null 代表空,where SPENOisnull; in null 代表不空9.查詢所有學(xué)生的學(xué)號(hào),使用外鍵,外鍵就是一個(gè)的主鍵是另一個(gè)表的字段select L.SPENAME from Lwhere 10.查詢計(jì)算機(jī)專(zhuān)業(yè)的學(xué)生學(xué)號(hào),名 w

4、here (select SPENO from L where SPENAME=計(jì)算機(jī)嵌套的查詢從里到外,11.select SPENO,count(*) from STU group by L where group by 12.查詢成績(jī)平均 select avg(SGRADE),sum(SGRADE),max(SGRADE) ,inSGAD)fom avg(SGRADE)sum(SGRADE) max(SGRADE) SQL集函數(shù)|count(distinct|all字段名|avg(distinct|all字段名|sum(distinct|all字段名|- 語(yǔ)grant 權(quán)限on 表明to 用戶名with grant revoke 權(quán)限on 表名from 用戶名列1.有with grant option時(shí) pri