1. ?????? ??? ? ??? ??

?????? ??? ???? ?? ?? ?????? ? ?? ??? ???? ???? ???. ??? ??? ?? ?? ??? ???? ?? ????? ?????? ???? ???? ?? ?? ?? ???? ???? ??? ?????. ????? ?? ??? ???? ????.

id: ?? ?, ?? ??.

name: ?? ??, varchar ??, ?? 20.

age: ?? ??, int ??.

sex: ?? ??, varchar ??, ?? 2.

t_score: CET-4 ?? ??, int ??.

total_score: ? ?? ??, ???.

?? SQL ?? ???? ??? ???? ?? ? ????.

CREATE TABLE 
student
 (
  
id
 int(11) NOT NULL AUTO_INCREMENT COMMENT '自增ID',
  
name
 varchar(20) NOT NULL DEFAULT '' COMMENT '學(xué)生姓名',
  
age
 int(11) NOT NULL DEFAULT '0' COMMENT '學(xué)生年齡',
  
sex
 varchar(2) NOT NULL DEFAULT '' COMMENT '學(xué)生性別',
  
t_score
 int(11) NOT NULL DEFAULT '0' COMMENT 'CET-4考試成績(jī)',
  
total_score
 int(11) NOT NULL DEFAULT '0' COMMENT '學(xué)生成績(jī)總和',
  PRIMARY KEY (
id
)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT='學(xué)生信息表';

?? ???? ?? ?? ???? ???? ?????.

INSERT INTO 
student
 (
name
, 
age
, 
sex
, 
t_score
, 
total_score
) VALUES ('張三', 20, '男', 550, 750), ('李四', 19, '女', 530, 700), ('王五', 22, '男', 610, 820), ('趙六', 23, '女', 590, 780), ('錢七', 21, '男', 500, 730);

2 ThinkPHP?? MySQL ??? ?????

??? Db ???? ??? ? ????. , ThinkPHP?? ?????? ??, ??, ??, ?? ?? ??? ?????. ?? ??? ??? ? MySQL ??? ???? ???. ??? ? ?? ???? ?? ??? ?????.

1. ?? ??? ???? ?? ??:

?? ??? ???? MySQL ??? ?? ??? ? ????. ?? ???? ID, ??, ?? ? ?? ??? ???? ?? ??? ?? ???? ??? ? ????:

$studentList = Db::name('student')->field(['id', 'name', 'age' ])->select();

$field ????? ???????. ? ????? ???? ??? ?? ??? ???? ???.

2. ??? ???? ???? ??:

? ?? ??? ??? ???? ?? ???? MySQL ??? ???? ????. ?:

//Query id, name ? age ??
$studentList = Db::name(' ?? ')->field('id, ??, ??')->select();

//t_score, total_score ? total Score ?? ?? (??? t_score? total_score? ?? ?????)
$studentList = Db::name('student')->field('t_score, total_score, (t_score+total_score) as Score')->select();

??? ??? ???? MySQL ??? ??? ? ??? ?? ??(??)?? ??? ? ????.

3. ?? ???? ???? ??:

?? ???? ???? ??? ?? ?? ?? ???? ???? ???. Student?? ?? ???? ?? ???? ??? ???? ??? ? ????

namespace appcommonmodel;

use thinkModel;

class Student ?? Model
{

//定義表名和主鍵
protected $table = 'student';
protected $pk = 'id';

}

???? Student ?? ???? ???? ??? ??? ? ????. ?? ?? ??:

//?? ?? ?? ?? ????
$studentList = Student::field(['id', 'name', 'age'])->select();

//?? ???? ?? ? ? ?? Points
$studentList = Student::field('name, (t_score+total_score) as Score')->select();

??? ?? MySQL ??? ???? ??? ? ???? ??????. SQL ?? ??? ????? ??? ? ????.

3. ThinkPHP?? MySQL ?? ?? ??? ?????

SQL ?? ?? ??? ? ??? ??? ???? ? ??? ???? ?? ??? ????. ?? ??, ?? ??? ??? ??? ? ???? ??? ?? ?? ??? ?? ????? ??? ?? ??? ??? ? ????.

$studentList = Db::name('student')->field('name, (SELECT count(*) FROM student as b WHERE b.total_score>s.total_score) as rank')->alias('s')->select();

? ??? ??? ?? ?? ??? ??? ??? ??? ? ????. ?? ?? ? ?? ??? ?? SQL ?? ??? ????.

SELECT name, (SELECT count(*) FROM student as b WHERE b.total_score>s.total_score) as rank FROM student s

ThinkPHP??? ?? ???? ???? MySQL ??? ??? ??? ???? ?? ???? ?? ??? ??? ? ????.

? ??? thinkphp?? mysql ??? ???? ??? ?? ?????. ??? ??? PHP ??? ????? ?? ?? ??? ?????!