【问题标题】:select distinct and count distinct in mysql在mysql中选择不同并计数不同
【发布时间】:2012-10-25 15:28:36
【问题描述】:

这是否可能从表列中选择不同的行并计算单个查询中每个不同字段的重复行数

$sql = "SELECT DISTINCT location and COUNT(DISTINCT location) 
        FROM ".$db_name.".$table_name 
        ORDER BY location ASC 
        LIMIT ". $start_page.",". $recordPer_page."";

【问题讨论】:

  • SELECT DISTINCT(location), COUNT(DISTINCT(location)) FROM ....

标签: php mysql


【解决方案1】:

您好,此查询对您有帮助:

SQLFIDDLE example

SELECT   `location`, COUNT(`location`) 
    FROM     tbl   
    GROUP BY `location`
    ORDER BY `location`

数据:

    ('Africa'),
    ('Viena'),
    ('Mexico'),
    ('Chicago'),
    ('Miami'),
    ('Chicago'),
    ('Viena'),
    ('London'),
    ('Viena');

结果:

| LOCATION | COUNT(`LOCATION`) |
--------------------------------
|   Africa |                 1 |
|  Chicago |                 2 |
|   London |                 1 |
|   Mexico |                 1 |
|    Miami |                 1 |
|    Viena |                 3 |

【讨论】:

    【解决方案2】:

    试试,

    SELECT   `location`, COUNT(DISTINCT `location`) 
    FROM     ....   
    GROUP BY `Location`
    ORDER BY ....
    LIMIT    ....
    

    【讨论】:

    • 在所有行的第二列中返回 1。
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