Question

我想将PHP $where作为大查询的一部分。我需要这样的东西：

SELECT * 
  FROM rf2aq_eb_events  
 WHERE id 
    IN ( SELECT event_id
              , SUM(number_registrants) summ 
           FROM rf2aq_eb_registrants 
          WHERE summ < event_capacity
       );

rf2aq_eb_events表格如下：

ID | event_capacity

1  | 7  
2  | 5  
3  | 9

rf2aq_eb_registrants表：

ID | events_id | number_registrants

1 | 1         | 6    
2 | 2         | 2   
3 | 3         | 4   
4 | 1         | 1    
5 | 2         | 0   
6 | 3         | 5

我需要从＆＃; rf2aq_eb_events＆＃39;中选择事件。对于具有注册人数量的事件＆lt;然后是event_capacity。有事件id = 2响应条件。

我已经尝试$where[] = 'a.id IN ( SELECT event_id FROM #__eb_registrants GROUP BY event_id HAVING sum(number_registrants) < a.event_capacity)';

了

它的工作方式与SQL类似，但在整个查询中不在php中。

下面我已经把php结果。

SELECT a.id, a.title, a.location_id, 
       a.event_capacity, a.event_date, a.individual_price, 
       a.thumb, a.early_bird_discount_date, a.early_bird_discount_amount, 
       c.name AS location_name 
FROM #__eb_events AS a 
      LEFT JOIN #__eb_locations AS c 
      ON a.location_id = c.id 
WHERE a.published =1 
      AND DATE(event_date) between date(CURDATE() + INTERVAL 7 DAY) 
      and date(CURDATE() + INTERVAL 26 DAY) 
      AND (
         cut_off_date = "0000-00-00 00:00:00" 
         OR DATE(cut_off_date) between NOW() and date(CURDATE() + INTERVAL 26 DAY)
      ) AND a.id IN ( 
           SELECT event_id 
           FROM #__eb_registrants 
           GROUP BY event_id 
           HAVING sum(number_registrants) < a.event_capacity
      ) AND a.id IN (
           SELECT event_id FROM #__eb_event_categories 
           WHERE category_id IN (6,7)
      ) AND a.access IN (1,1) 
 ORDER BY a.event_date 
 LIMIT 4

Answer 1

您不必使用子查询。

SELECT `e`.* FROM `rf2aq_eb_events` as `e`
LEFT JOIN `rf2aq_eb_registrants` as `r`
ON `r`.`events_id`=`e`.`ID`
GROUP BY `r`.`events_id`
HAVING SUM(`r`.`number_registrants `) < `e`.`event_capacity`

Answer 2

您无法在SUM中使用聚合的结果（例如WHERE），您可以在HAVING中使用它，但您需要执行GROUP BY在这种情况下：

SELECT * FROM `rf2aq_eb_events` e
WHERE `id` IN (
 SELECT `event_id` 
 FROM `rf2aq_eb_registrants` r 
 GROUP BY `event_id` 
 HAVING sum(`number_registrants`) <  `event_capacity`
)

SELECT * FROM表WHERE`id` in ...和sum（）less

2 个答案: