在mysql中选择distinct和count distinct

Question

这是否可行从表列中选择不同的行，并为单个查询中的每个不同字段计算重复行

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

Answer 1

您好此查询可以帮助您：

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 |

Answer 2

尝试，

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