收集MYSQL数据库中列中每个唯一单元格的总计

Question

以下是用于从数据库中提取数据的当前代码 $query = "SELECT username,time,UNIX_TIMESTAMP(time) as timestamp,UNIX_TIMESTAMP(active) as activestamp,IP FROM ".$table_name." WHERE success='1' ORDER BY active DESC";

以下是一组示例数据（删除了所有不重要的字段）
ID | username
_01 | admin
_02 | admin
_03 | bob
_04 | jill

我想要的是每个用户出现的总次数，例如：
admin (2)
bob (1)
jill (1)

我需要将这个COUNT(IF(name = 'admin', 1, NULL)) AS login_totals的内容添加到我向您展示的原始查询中，但我无法弄清楚正确的代码。我的示例中的admin名称必须是当前的用户名，所以我只是将“用户名”放在那里吗？

Answer 1

试试这个：我添加了count(*) and the group by

 $query = "SELECT username,time,
UNIX_TIMESTAMP(time) as timestamp,
UNIX_TIMESTAMP(active) as 
activestamp,IP, count(*) 
FROM ".$table_name." WHERE success='1' 
group by username 
ORDER BY active DESC";

看一下这个博客：http://www.mysqlperformanceblog.com/2007/04/10/count-vs-countcol/

Answer 2

在COUNT(username)子句中添加SELECT，在查询末尾添加GROUP BY username。

Answer 3

SELECT
   username,count(username)
   FROM ".$table_name." WHERE success='1' 
GROUP BY username
ORDER BY active DESC";