a)
CREATE TABLE `sa` (
`s` VARCHAR( 10 ) NOT NULL ,
`sn` VARCHAR( 12 ) NOT NULL ,
`sex` TINYINT( 1 ) NOT NULL,
`sa` INT NOT NULL ,
PRIMARY KEY ( `s` )
) ;CREATE TABLE `sb` (
`c` VARCHAR( 10 ) NOT NULL ,
`cn` VARCHAR( 12 ) NOT NULL ,
PRIMARY KEY ( `c` )
) ;CREATE TABLE `sc` (
`s` VARCHAR( 10 ) NOT NULL ,
`c` VARCHAR( 12 ) NOT NULL ,
`grade` FLOAT NOT NULL,
PRIMARY KEY ( `s` )
) ;b)
名字,性别,课程名,学号
select sn,sex,cn,s from sa,sc,sb where sc.s=sa.s and sb.c=sc.cc)从student表里查询名字,性别,年龄+1。
select sn,sex,sa+1 from sa
CREATE TABLE `sa` (
`s` VARCHAR( 10 ) NOT NULL ,
`sn` VARCHAR( 12 ) NOT NULL ,
`sex` TINYINT( 1 ) NOT NULL,
`sa` INT NOT NULL ,
PRIMARY KEY ( `s` )
) ;CREATE TABLE `sb` (
`c` VARCHAR( 10 ) NOT NULL ,
`cn` VARCHAR( 12 ) NOT NULL ,
PRIMARY KEY ( `c` )
) ;CREATE TABLE `sc` (
`s` VARCHAR( 10 ) NOT NULL ,
`c` VARCHAR( 12 ) NOT NULL ,
`grade` FLOAT NOT NULL,
PRIMARY KEY ( `s` )
) ;b)
名字,性别,课程名,学号
select sn,sex,cn,s from sa,sc,sb where sc.s=sa.s and sb.c=sc.cc)从student表里查询名字,性别,年龄+1。
select sn,sex,sa+1 from sa
select sn,sex,cn,s from sa,sc,sb where sc.s=sa.s and sb.c=sc.c order by sc.grade asce)
select sn,sex,cn,s from sa,sc,sb where sc.s=sa.s and sb.c=sc.c where sc.grade>80 order by sc.grade asc limit
(这里用ADODB类库; mysql函数/PDO都差不多)
$pageSize=20;
$p=(intval($_GET["p"])<=0)?1:intval($_GET["p"]);
$offset=($p-1)*$pageSize;
$sql="select sn,sex,cn,s from sa,sc,sb where sc.s=sa.s and sb.c=sc.c where sc.grade>80 order by sc.grade asc limit ".$offset.",".$pageSize;$rs=$dbconn->Execute($sql);
while(!$rs->EOF) {
...
$rs->MoveNext();
}