MySQL 查询中的查询

Question

我有以下查询，它可以很好地查询 asterisk cdr 中所有错过的队列调用，但它是重复的。也就是说，如果队列调用中有两个分机，则将其分类为两个未接来电。

查询:

SELECT count( * ) as today_total_8
    FROM cdr 
    WHERE channel LIKE '%from-queue%' 
        AND disposition='NO ANSWER' 
        AND DATE(`calldate`) = DATE(CURDATE())

对于所有两个结果，calldate 列的值相同；如何将其添加到上述查询中以显示未接来电的计数？

SELECT 返回的数据不带计数:

calldate            channel                 disposition     
------------------------------------------------------------------------
2014-02-08 01:15:02     Local/201@from-queue-00000012;2     NO ANSWER
2014-02-08 01:15:02     Local/200@from-queue-00000013;2     NO ANSWER
2014-02-08 00:18:04     Local/201@from-queue-00000010;2     NO ANSWER
2014-02-08 00:18:04     Local/200@from-queue-00000011;2     NO ANSWER

我怎样才能做到这一点，因为我希望我的计数为 2？

Answer 1

SELECT count(distinct calldate ) as today_total_8
FROM cdr 
WHERE channel LIKE '%from-queue%' 
    AND disposition='NO ANSWER' 
    AND DATE(`calldate`) = DATE(CURDATE())
GROUP BY calldate