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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?)

?? ?? ??




????


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      <label id="jxxus"></label>

        ??

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

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




        category

        ??? ??

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        +---------+
        ??? ??
        ?? ??


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        ?? ??

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



        mysql> ?? = 29? ??? * ??;
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        | ??? | ?? |
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        ?? ???

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

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        mysql> '???';

        +------+------------+---------+----------+------+----- +
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        1 | ???? 120.02 | +------+------------+---------+----------+------+----- +
        1?(0.00?)


        ?? ?? ??

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        ??? ???? ???:

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        ??? ??
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        | ??? ?? |

        +---------+---------+

        | 10 | ???? | 810 |

        | 8 | ?? | 260.23 |
        | 1 | ???? | 11 | ?? | 23.4 |
        | 20.15 | -+-- -------+
        ?? ? 12? ?(0.00?)

        ?? ?? ??

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




        Category

        ??? ??


        ?? ??

        ????? ?? ?? ?? 1 ?? ??? ?? ??,... ...Field n desc|asc;?? ??

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        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?)


        ?? ?? ??

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

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        ?? ???? id, ??? ??, ?? ??? ???? ??? ?? ?????? ?????. ??? ?? ????? age? ???? ?????? ?????
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        +----+------------+----------+---------- - +------+------+
        | ??? | ?? |
        +-------+--- - ----+----------+-----+
        | 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?)

        ?? ?? ?? ??

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

        ????

        ??? ??

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        ??: ? ?? ???? 0???.

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        ? ?????. +----+------------+---------+
        | ??? | ?? |
        +----+------------+---------+
        1 | ???? 120.02 |
        2 | ??? 260.23 |
        3 | ???? 150.86 |
        +----+------------+---------+
        3? ?? (0.00?)

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        | ??? | ?? |
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        4 | ??? 810 |
        5 | ??? 20.15 |
        6 | ?? 313 |
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        3? ??(0.00?)

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        ??? 1? ?? 0,10
        ??? 2? ?? 10,10
        ??? 3? ?? 20,10

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        ?? ??????? ?? ?? ?? ???, ??
        ?? ?? 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 |
        +---------+
        1? ??(0.00?)

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        ??(??) |
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        498.24833393096924 |
        +---------+
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        | ??(??) |
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        5978.980007171631 |
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        mysql> ??? ??(??) ??;
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        mysql> ??? ??(??) ??;
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        20.149999618530273 |
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        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?)

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


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        | ???(?) |
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        ??? ??

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

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

        Category??? ??
        ?? ??select * from table group by field with Rollup
        Exampleselect count(province),province from Money Group by Province with ?? ;
        ?? ???? ?? ?? ??? ???

        ? ??? ??? ?? ?? ??? ?? ?? ?? ?? ?? 12?? NULL? ??? ????.

        mysql> ??? ?? ??? ?? ???? ??(??) ??;
        +------+------------+
        | ???(?) |
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        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?)


        ???? ??

        ||
        <?php echo "Hello Mysql"; ?>
        • <rt id="jxxus"><optgroup id="jxxus"></optgroup></rt>