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Mysql ?? ??? ??, ??, ??

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

money?? ??? ??? ??????.

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

CREATE TABLE money (
     id INT NOT NULL AUTO_INCREMENT ,
     username VARCHAR(50) NOT NULL ,
     balance FLOAT NOT NULL ,
     province VARCHAR(20) NOT NULL ,
     age TINYINT UNSIGNED NOT NULL ,
     sex TINYINT NOT NULL ,
     PRIMARY KEY (id(10))
) ENGINE = InnoDB CHARACTER SET utf8;

??? ??? ???? ??? ?? ?????:

idusernamebalanceprovinceagesex
1 ???? 120.02???291
2???260.23??40 0
3????150.86 Shandong40 1
4Jing Boran810Liaoning271
5Li Bingbing 20.15???? 430
6?? 313Shandong631
7Yang Mi123Beijing 300
8??? 456Beijing29 1
9Liu Yan23.4Hunan360
10Zhao Benshan3456??? 631
11王峰 34.32Beijing441
12Guo Degang 212Tianjin431

??:
balance? ??? ?????.
province? ??? ?????.

?? ??

Category??? ??
?? ??select * from table;
??? * from Money;
?? ?? ? ?? ???? ?? ??? ?? ?? ??

??: "*"? ?? ??? ???? ???? ?? ??????. ? ?? ?? ??? ?????.

mysql> select * from Money;
+----+---- ---- ---+---------+---------+-----+
| ??? | ?? |
+----+------------+----------+------------+--- ---+ -----+
| 120.02 | ??? | 40 | 1 |
| 810 | ??? | 20.15 | ?? 6 | | ?? | 30 | 456 | ?? | 36 | ??? | 1 |
| 34.32 | ??? 1 | --------+------ -----+------------+------+------+
12? ? ?? (0.00?)

?? ?? ??




????


??? ?? 語 ?? ?? ????? ?? ?? ID, ??? ??, ?? ??; ??? ??, ?? ?? ?? 

       ?? 
      mysql> ID, ??? ??, ?? ??;
      +----+----------+----------+
      | ID |
       +----+------------+
      | 1 | ???? | 260.23 |
      | ? ??? | 
      | 5 | ??? | 313 |
      | 8 | 
      | 23.4 | 10 | ???? | 34.32 |
      | 212 | ---+------- --+
      ??? 12? ?(0.00?)

      ???? ?? ???? ?? ?? ?? ?? ??




      category
      ??? ??
      +------+| 27 || | 63 || 30 || 36 || 44 |8?(0.00?)??? ?? whereselect field from Table where ??;
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      +---------+
      ??? ?? 
      ?? ??

      Example

      select * from Money where age = 29;



      ?? ??

      ?? ??? 29? ?? ??? ?????. ?? ???



      mysql> ?? = 29? ??? * ??;
      +----+----------+---------+--------- - +------+----+
      | ??? | ?? |
      +--------+--- - ----+--------+----+
      | 1 | ???? 120.02 | ??? | | 456 | ??? | 29 | 1 |
      +----+----------+--------+- - ---+------+
      2? ??(0.00?)
      where? ?? ? ?? ??
      ?? ?????? ?? ???? ?? ??? ?????. ?? ??? where ?? ??? ??? '='???. 
      ?? >, <, >=, <=, !=; 
      symbolExplanation>>? ?? ?? ???? ??? ?? ????. ; <?? ?? >=?? ??? ?? <=?? ??? ??  !=??? = ?? 
      ?? ???
      ?? ??? or ? ?? ?? ???? ???? ?? ?? ?? ??? ??? ?? ????
      SymbolExplan ationoror andand
       
       
       ?? ??? ?? ???????. 
      Type???? ??? * ? ID? <10?????? ??? 10?? ?? ID? ???? ??='Hubei'
      mysql> '???';
      
 +------+------------+---------+----------+------+----- +
      
 | ??? | ?? |
 +------+------------+---------+----------+------+----- +
      
 1 | ???? 120.02 |
 +------+------------+---------+----------+------+----- +
      
 1?(0.00?)


      ?? ?? ??
      Category??? ???? ???? ?? ???? ????? ?? ???  ?? ???? ????? ID, ??? ??, ?? ??;?? ???? ???? ID, ??? ??, ?? ??? ???? ??? ?? ?????? ??
      ??? ???? ???: 
       
      mysql> ?? ???? ????? ID, ??? ??, ?? ??;+----+------------+---------+
      ???  ?? 
      asc????, ?? ??? ? ???(???) 
      desc ????, ?? ???? ?? ?? ? ?? ??? order by? ?????. ??? desc ? asc? ?? ??? ??????. desc? ???? ?????? ???? ?? ????, asc? ?????? ???? ?? ?????. ???? ?? ??? ???? ?????? ?????. 
      | ??? ?? |
      +---------+---------+
      | 10 | ???? | 810 |
       | 8 | ?? | 260.23 |
      | 1 | ???? | 11 | ?? | 23.4 |
      | 20.15 | -+-- -------+
      ?? ? 12? ?(0.00?)

      ?? ?? ??

      order by ??? ??? ?? ?? ?? ??? ? ? ??? ??? ?? ??? ??? ?????. ??? ????. ??? ?? ??? ?? ??? ?? ??? ?? ?? ??? ? ?? ?? ??? ?? ?????. 




      Category

      ??? ??


      ?? ??
      ????? ?? ?? ?? 1 ?? ??? ?? ??,... ...Field n desc|asc;?? ??
      * ??: ? ?? ??? ?? ??? ???? ?? ??. ? ?? ?? ?? ??? ???? ????. ? ?? ? ?? ??? ???? ????. *
      mysql> ?? ??, ?? ?????? ??? ??, ??? ??, ??? ?????.
      
 +----+------------+---------+
      
 | ??? | ?? |
      
 +----+------------+---------+
      
 10 | ???? |
 4 | ??? 810 |
      
 8 | 456 |
      
 6 | ?? 313 |
      
 2 | ??? 260.23 |
      
 12 | ??? |
 3 | ???? 150.86 |
      
 7 |?? 123 |
      
 1 | ???? 120.02 |
      
 11 | ?? 34.32 |
      
 9 | ??? |
 5 | ??? 20.15 |
      
 +----+------------+---------+
      
 ??? 12? ?(0.00?)


      ?? ?? ??
      ?? ?? ??? ?? ??? ?? ??? ?? ??? ????? ?? ???? ???? ?? ?? ?? ?????. 
      ?   id, ??? ??, ??? ?? desc, age asc? ?????? ?? 
       ?? ???? id, ??? ??, ?? ??? ???? ??? ?? ?????? ?????. ??? ?? ????? age? ???? ?????? ?????
      ??????? ???? ???? ???? ?? ??;Example ?? 5?? ID, ??? ??, ?? ??;  ? ?? ?? 5?? ??? ??
      mysql> ?? ?? 5?? * ??;
      +----+------------+----------+---------- - +------+------+
      | ??? | ?? |
      +-------+--- - ----+----------+-----+
      | 1 | ???? 120.02 | ? | ????? | 43 | 0 | ---+--- ---+
      5? ??(0.00?)

      ?? ?? ?? ? ??


      Category
       
      ??? ???? ???? ?? ?? ??? ??? ?? ??? ?? QuantityExampleselect id,username, Balance from Money order by Balance desc Limit 5;?? ?????? ??, ?? 5?? ??? ??? ??+----+------------+---------+| ??? | ??? ?? | ?? |+---------+---------+
        mysql> ID, ??? ??, ????? ?? ?? ?? 5;
      | 810 |
       | 6 | ?? | 260.23 |
      +-------+ ------ -+
      5? ??(0.00?)

      ?? ?? ?? ??

      0?? ???? 3?? ???? ???? ?????. ? ?? ????? 3? ???? ? ???? ????. 6?? ????? 4?? ???? ????? ??? ?? ???? 

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

      ????
      ??? ??
      ??? ??
      ??: ? ?? ???? 0???. 
      mysql> ID, ??? ??, ?? ?? 0,3;
      ? ?????.
 +----+------------+---------+
      
 | ??? | ?? |
      
 +----+------------+---------+
      
 1 | ???? 120.02 |
      
 2 | ??? 260.23 |
      
 3 | ???? 150.86 |
      
 +----+------------+---------+
      
 3? ?? (0.00?)
      3??? 3? ? ???? ? ????? 
      mysql> ID, ??? ??, ?? ?? 3,3;
      ? ?????.
 +----+------------+---------+
      
 | ??? | ?? |
      
 +----+------------+---------+
      
 4 | ??? 810 |
      
 5 | ??? 20.15 |
      
 6 | ?? 313 |
      
 +----+------------+---------+
      
 3? ??(0.00?)
      ? ????? ?? ?????? ???? ?????. 
      ???? 10?? ???? ??? ??: 
      ??? 1? ?? 0,10
      ??? 2? ?? 10,10
      ??? 3? ?? 20,10
      ?... ...
      ?? ?? ?? 
      1. ? ??? ?? ?? ??? ??? ?? ???? 
      2. ??? ????? ?? ?? ??? ???? ???? ??? ?????? 
      3. ???? ??? ?? ??? ?? ??? ??? ?? ???? 
      4. ?? ???? ??? ?? ??? ??? ?? ???? 
      ?? ????? ???? ? ?? ?? ??? ????. 
      ?? ??????? ?? ?? ?? ???, ??
      ?? ?? 0, 3?? ID, ??? ??, ?? ?? ; 
      ? ?? ????? ? ?? ???? ?????
       
       ??  ?? 
      sumsum 
      count?? ?? 
      max ??? 
      min???
      avgAverage
      ??: ?? ?? mysql ??? ??? ? ??? ?? ?? ????. ??? ?? ????? ???? ?? ?? ?? ?? ?????? ?? ???? ??? ?? ?? ?? ??? ??? ????. MySQL ??? ???? ?? ?? ??? ??? ??? ?? ?? ?? ??? ???? ??? ?? ??? ??? ??? ????. 
      ??????? ??
      ?? ??select function(field) from table
      Exampleselect count(id) from Money 
       
      ?? ?  ?? ???? ? ID ?? ?????
      mysql> ??? ??(id) ??;
      
 +----------+
      
 | ??(ID) |
      
 +----------+
      
 12 |
      
 +----------+
      
 1? ??(0.00?)
      ??? ??? ??? ?? ????! as ???? ?????. 
      mysql> ??? ??? count(id)? ?????.
      
 +---------+
      
 |?? |
      
 +---------+
      
 12 |
      
 +---------+
      
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      ?? ?? ??
      mysql> ??? ??(??) ??;
      
 +---------+
      
 ??(??) |
      
 +---------+
      
 498.24833393096924 |
      
 +---------+
      
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      ?? ??
      mysql> ??? ??(??) ??;
      
 +------+
      
 | ??(??) |
      
 +------+
      
 5978.980007171631 |
      
 +------+
      
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      ?? ?? ??
      mysql> ??? ??(??) ??;
      
 +-------------+
      
 |??(??) |
      
 +-------------+
      
 3456 |
      
 +-------------+
      
 1? ??(0.00?)
      ?? ?? ??
      mysql> ??? ??(??) ??;
      
 +---------+
      
 |??(??) |
      
 +---------+
      
 20.149999618530273 |
      
 +---------+
      
 1? ??(0.00?)
      group by
      ???? ??? ??? ???? ???? ? ?? ? ????. ??? ??? ?????. ?, ??? ?????. ??? 
       ?? ? ???? ???
      mysql> ??? ?? ???? * ??;
      +----+------------+---------+--------- -+----+------+
      | ??? | ?? |
      +------+--- ------+--------+-----+
      | 7 | ??? 30 | Guo Degang | ?? | 0 |
      | 4 | ??? | 20.15 | --------------+-- -------+------------+------+------+
       
      ??? ???(??) ? ?:

      mysql> deptno ??, emp ???? deptno?? ??(1);
      +---------+------------+
      | ????(1) |
      +-------+
      | 1 | 1 |
      | 5 | 4 |
      +---------+--- -------+
      4? ??(0.04?)

      ? ?? ?? ???? ?????

       
      mysql> ??? ?? ???? ??(??), ?? ??;
      
 +------+------------+
      
 | ???(?) |
      
 +------+------------+
      
 3 | ??? |
      
 | 1 1 | ?? |
      
 3 |?? |
      
 1 1 |
 |??? |
      
 2 | ??? |
      
 | ????? |
      
 +------+------------+
      
 7? ??(0.00?)


      ??? ??

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

       ?? ??? ???? ???? ??? ??? ?? ? ??? ???? ????. 
       
      Category??? ??
      ?? ??select * from table group by field with Rollup
      Exampleselect count(province),province from Money Group by Province with ?? ; 
      ?? ???? ?? ?? ??? ???
      ? ??? ??? ?? ?? ??? ?? ?? ?? ?? ?? 12?? NULL? ??? ????. 
      mysql> ??? ?? ??? ?? ???? ??(??) ??;
      
 +------+------------+
      
 | ???(?) |
      
 +------+------------+
      
 3 | ??? |
      
 | 1 1 | ?? |
      
 3 |?? |
      
 1 1 |
 |??? |
      
 2 | ??? |
      
 | ????? |
      
 12 |NULL |
      
 +------+------------+
      
 8? ??(0.00?)
      ?? ?? ??? ??????.
      having ?? where? ????? ? ? ??? ???? ????. 
      having? ??? ???? ??? ??? ??? ???? 
      Category??? ???? ??select * ????? ??? ?? ???? ???Examplecount(province)? ??? ?? ???? ? ???? >2;?? ???? ????? ??? ???? ??? ??? 2?? ? ???? ??? ?????
      mysql> ??? count(province)? ????, ???? ? ???? ??? >2;
      
 +---------+----------+
      
 | ?? |
      
 +---------+----------+
      
 3 | ??? |
      
 3 |?? |
      
 +---------+----------+
      
 2? ??(0.00?)
      SQL ?? ????
      ? ???? ??? ?? ?? ?? ??????. 
      ?? ?? ???? ? ? ?? ?????. ?? SQL ?? ???? ?? ??? ??? ????. 
      SELECT 
      
 [?? 1 [?? 1], [??(?? 2),]...?? n] 
      
 FROM ??? ??
      
 [WHERE ?? ??]
      
 [GROUP BY ??]
      
 [HAVING where_continition]
      
 [????]
      
 [?? ??]
      ??: []? ? ??? ?? ??? ??? ? ????. 
      ?? ??? ??? ?? ?????. 
      Keywords Description
      selectSelected columns
      fromtable
       
       ???? ??
       
       group by?? ??? ??? ?? grouping ??
      order bysort attribute
      limit?? ??? ??, ??? ?? ????
      ????? ?????. , ?? ??? ??(id, ??? ??, ??, ??)? ?????. id>1?? ??? 50?? ?? ???. ????? ??? ?????. ?????? ??? ID? ????, 3?? ??? ????? ?????. 
      ????? ??? ?? SQL ?? ???? ?? ??? ??? ????. 
      mysql> ?? 3;
      
 +------+------------+---------+----------+
      
 | ??? | ?? |
 +------+------------+---------+----------+
      
 12 | ??? 212 |
 7 | ?? |
 4 | ??? 810 |
      
 +------+------------+---------+----------+
      
 3? ?? (0.00?)


      					
				
			???? ??
			

			
      

				
      
			        
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      <?php
echo "Hello Mysql";
?>