MySQL-使用子查詢分組

Question

我在使用子查詢和某些分組時遇到麻煩。 子查詢從整個表中進行選擇，而不僅僅是單個組...我的代碼

SELECT SEC_TO_TIME(TIME_TO_SEC(call_start) - TIME_TO_SEC(call_start)%(30*60)) AS intervals, 
       COUNT(*) AS OFFERED, 
       SUM(agent_duration) AS AGENT_SUM, 
       SUM(TIME_TO_SEC(TIMEDIFF(dequeue_time, enqueue_time))) AS ANS_TIME_SUM, 
       COUNT(DISTINCT agent_username) AS UNIQUE_AGENTS, 
       (SELECT COUNT(*) FROM call_detail
        WHERE TIME_TO_SEC(TIMEDIFF(dequeue_time, enqueue_time)) < 40) AS SLA, 
       SUM(queue_duration) AS TOTAL_QUEUE_TIME 
FROM call_detail
WHERE DATE(call_start) = CURDATE()
GROUP BY intervals

我的目標是讓子查詢僅返回在特定間隔內TIMEDIFF結果小於40的記錄數

謝謝。

Answer 1

我認為您不需要為此的子查詢。 只需執行條件聚合：

SELECT SEC_TO_TIME(TIME_TO_SEC(call_start) - TIME_TO_SEC(call_start)%(30*60)) AS intervals, 
       COUNT(*) AS OFFERED, 
       SUM(agent_duration) AS AGENT_SUM, 
       SUM(TIME_TO_SEC(TIMEDIFF(dequeue_time, enqueue_time))) AS ANS_TIME_SUM, 
       COUNT(DISTINCT agent_username) AS UNIQUE_AGENTS, 
       sum(case when TIME_TO_SEC(TIMEDIFF(dequeue_time, enqueue_time)) < 40 then 1 else 0 end) as SLA,
       SUM(queue_duration) AS TOTAL_QUEUE_TIME 
FROM call_detail
WHERE DATE(call_start) = CURDATE()
GROUP BY intervals;

您將使用子查詢獲取所有記錄的總數，而不是受where子句或group by影響的記錄。