• mysql中limit用法


    用查询语句的时候,经常要返回前几条或者中间某几行数据,这个时候怎么办呢?不用担心,mysql已 经为我们提供了这样一个功能。

    LIMIT 子句可以被用于强制 SELECT 语句返回指定的记录数。LIMIT 接受一个或两个数字参数。参数必须是一个整数常量。如果给定两个参数,第一个参数指定第一个返回记录行的偏移量,第二个参数指定返回记录行的最大数目。初 始记录行的偏移量是 0(而不是 1): 为了与 PostgreSQL 兼容,MySQL 也支持句法: LIMIT # OFFSET #。

    实例:

    mysql> use sppeivan;
    Database changed
    mysql> select * from employee; // 返回所有结果
    +------------+------------+--------+-------------+
    | username   | password   | gender | cellphone   |
    +------------+------------+--------+-------------+
    | ewrew      | erewr      | MAN    | 13618889076 |
    | ewrwerw32r | 324324     | MAN    | 13618889076 |
    | grrrrr     | r44343     | WOMAN | 13618889076 |
    | pansong    | erewrwe    | MAN    | 13618889076 |
    | ret43t43t | 43t43      | MAN    | 13618889076 |
    | ret44t4    | r4tgr      | WOMAN | 13618889076 |
    | tttt       | 4et        | WOMAN | 13618889076 |
    | wr34r      | retre      | MAN    | 13618889076 |
    | xxx     | safe       | MAN    | 13618889076 |
    | hhh       | ewrwer     | MAN    | 13618889076 |
    | hg       | 6574326543 | MAN    | 13618889076 |
    | ps       | ewrwe      | MAN    | 13618889076 |
    | zhu       | werew      | MAN    | 13618889076 |
    +------------+------------+--------+-------------+
    13 rows in set (0.01 sec)

    mysql> select * from employee limit 3 7;
    ERROR 1064 (42000): You have an error in your SQL syntax
    corresponds to your MySQL server version for the right s
    line 1
    mysql> select * from employee limit 3, 7; // 返回4-11行
    +-----------+----------+--------+-------------+
    | username | password | gender | cellphone   |
    +-----------+----------+--------+-------------+
    | pansong   | erewrwe | MAN    | 13618889076 |
    | ret43t43t | 43t43    | MAN    | 13618889076 |
    | ret44t4   | r4tgr    | WOMAN | 13618889076 |
    | tttt      | 4et      | WOMAN | 13618889076 |
    | wr34r     | retre    | MAN    | 13618889076 |
    | xxx     | safe     | MAN    | 13618889076 |
    | hhh      | ewrwer   | MAN    | 13618889076 |
    +-----------+----------+--------+-------------+
    7 rows in set (0.00 sec)

    mysql> select * from employee limit 3,-1; // 错误语法
    ERROR 1064 (42000): You have an error in your SQL syntax
    corresponds to your MySQL server version for the right s
    t line 1


    mysql> select * from employee limit 3,1; // 返回第4行
    +----------+----------+--------+-------------+
    | username | password | gender | cellphone   |
    +----------+----------+--------+-------------+
    | pansong | erewrwe | MAN    | 13618889076|
    +----------+----------+--------+-------------+
    1 row in set (0.00 sec)

    mysql> select * from employee limit 3; // 返回前3行

    +------------+----------+--------+-------------+
    | username   | password | gender | cellphone   |
    +------------+----------+--------+-------------+
    | ewrew      | erewr    | MAN    | 13618889076 |
    | ewrwerw32r | 324324   | MAN    | 13618889076 |
    | grrrrr     | r44343   | WOMAN | 13618889076 |
    +------------+----------+--------+-------------+
    3 rows in set (0.00 sec)


    mysql> select * from employee limit 10; // 返回前10行

    +------------+----------+--------+-------------+
    | username   | password | gender | cellphone   |
    +------------+----------+--------+-------------+
    | ewrew      | erewr    | MAN    | 13618889076 |
    | ewrwerw32r | 324324   | MAN    | 13618889076 |
    | grrrrr     | r44343   | WOMAN | 13618889076 |
    | pansong    | erewrwe | MAN    | 13618889076 |
    | ret43t43t | 43t43    | MAN    | 13618889076 |
    | ret44t4    | r4tgr    | WOMAN | 13618889076 |
    | tttt       | 4et      | WOMAN | 13618889076 |
    | wr34r      | retre    | MAN    | 13618889076 |
    | xxx     | safe     | MAN    | 13811588469 |
    | hhh       | ewrwer   | MAN    | 13618889076 |
    +------------+----------+--------+-------------+
    10 rows in set (0.00 sec)

    mysql> select * from employee limit 9,1; // 返回第10行

    +----------+----------+--------+-------------+
    | username | password | gender | cellphone   |
    +----------+----------+--------+-------------+
    | hhh     | ewrwer   | MAN    | 13816668468 |
    +----------+----------+--------+-------------+
    1 row in set (0.00 sec)

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  • 原文地址:https://www.cnblogs.com/martin1009/p/2233088.html
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