时间:2021-07-01 10:21:17 帮助过:5人阅读
MAX() 函数返回指定列的最大值。
- <span style="color: #0000ff;">SELECT</span> <span style="color: #ff00ff;">MAX</span>(column_name) <span style="color: #0000ff;">FROM</span> table_name;
在本教程中,我们将使用 RUNOOB 样本数据库。
下面是选自 "Websites" 表的数据:
- <span style="color: #808080;">+</span><span style="color: #008080;">--</span><span style="color: #008080;">--+--------------+---------------------------+-------+---------+</span>
- <span style="color: #808080;">|</span> id <span style="color: #808080;">|</span> name <span style="color: #808080;">|</span> url <span style="color: #808080;">|</span> alexa <span style="color: #808080;">|</span> country <span style="color: #808080;">|</span>
- <span style="color: #808080;">+</span><span style="color: #008080;">--</span><span style="color: #008080;">--+--------------+---------------------------+-------+---------+</span>
- <span style="color: #808080;">|</span> <span style="color: #800000; font-weight: bold;">1</span> <span style="color: #808080;">|</span> Google <span style="color: #808080;">|</span> https:<span style="color: #808080;">//</span>www.google.cm<span style="color: #808080;">/</span> <span style="color: #808080;">|</span> <span style="color: #800000; font-weight: bold;">1</span> <span style="color: #808080;">|</span> USA <span style="color: #808080;">|</span>
- <span style="color: #808080;">|</span> <span style="color: #800000; font-weight: bold;">2</span> <span style="color: #808080;">|</span> 淘宝 <span style="color: #808080;">|</span> https:<span style="color: #808080;">//</span>www.taobao.com<span style="color: #808080;">/</span> <span style="color: #808080;">|</span> <span style="color: #800000; font-weight: bold;">13</span> <span style="color: #808080;">|</span> CN <span style="color: #808080;">|</span>
- <span style="color: #808080;">|</span> <span style="color: #800000; font-weight: bold;">3</span> <span style="color: #808080;">|</span> 菜鸟教程 <span style="color: #808080;">|</span> http:<span style="color: #808080;">//</span>www.runoob.com<span style="color: #808080;">/</span> <span style="color: #808080;">|</span> <span style="color: #800000; font-weight: bold;">5000</span> <span style="color: #808080;">|</span> CN <span style="color: #808080;">|</span>
- <span style="color: #808080;">|</span> <span style="color: #800000; font-weight: bold;">4</span> <span style="color: #808080;">|</span> 微博 <span style="color: #808080;">|</span> http:<span style="color: #808080;">//</span>weibo.com<span style="color: #808080;">/</span> <span style="color: #808080;">|</span> <span style="color: #800000; font-weight: bold;">20</span> <span style="color: #808080;">|</span> CN <span style="color: #808080;">|</span>
- <span style="color: #808080;">|</span> <span style="color: #800000; font-weight: bold;">5</span> <span style="color: #808080;">|</span> Facebook <span style="color: #808080;">|</span> https:<span style="color: #808080;">//</span>www.facebook.com<span style="color: #808080;">/</span> <span style="color: #808080;">|</span> <span style="color: #800000; font-weight: bold;">3</span> <span style="color: #808080;">|</span> USA <span style="color: #808080;">|</span>
- <span style="color: #808080;">|</span> <span style="color: #800000; font-weight: bold;">6</span> <span style="color: #808080;">|</span> 百度 <span style="color: #808080;">|</span> https:<span style="color: #808080;">//</span>www.baidu.com<span style="color: #808080;">/</span> <span style="color: #808080;">|</span> <span style="color: #800000; font-weight: bold;">4</span> <span style="color: #808080;">|</span> CN <span style="color: #808080;">|</span>
- <span style="color: #808080;">|</span> <span style="color: #800000; font-weight: bold;">7</span> <span style="color: #808080;">|</span> stackoverflow <span style="color: #808080;">|</span> http:<span style="color: #808080;">//</span>stackoverflow.com<span style="color: #808080;">/</span> <span style="color: #808080;">|</span> <span style="color: #800000; font-weight: bold;">0</span> <span style="color: #808080;">|</span> IND <span style="color: #808080;">|</span>
- <span style="color: #808080;">+</span><span style="color: #008080;">--</span><span style="color: #008080;">--+---------------+---------------------------+-------+---------+</span>
下面的 SQL 语句从 "Websites" 表的 "alexa" 列获取最大值:
- <span style="color: #0000ff;">SELECT</span> <span style="color: #ff00ff;">MAX</span>(alexa) <span style="color: #0000ff;">AS</span> max_alexa <span style="color: #0000ff;">FROM</span> Websites;
执行以上 SQL 结果如下所示:
SQL MAX() 函数
标签:ack 最大值 alt lex 百度 body -- https url