MySQL 获取同一表中存在相应行的行 - MySQL get rows where corresponding row in same table exists

MySQL get rows where corresponding row in same table exists

本文关键字：存在获取 MySQL | 更新日期: 2023-09-27

我正在尝试根据一些基本的 where 子句从表中获取行，现在我想在末尾包含一个"AND EXISTS"子句。我的代码如下：

$stmt = $mysqli->prepare("SELECT object_id FROM ".
          $db_table_prefix."user_events
          WHERE LPAD(start_timestamp,15,'0') < LPAD(?,15,'0')
          AND event_id = ?
          AND EXISTS ( 
            SELECT * FROM ".$db_table_prefix."user_events
              WHERE LPAD(start_timestamp,15,'0') > LPAD(?,15,'0')
              AND event_id = ? )
        ");

我遇到的问题是我不知道如何从 AND EXISTS 子查询中的主查询中指定列值。

我正在寻找一种方法将这一点附加到子查询中：

AND object_id = **object_id from main query**

任何帮助表示赞赏

此外，在子查询的表中添加了别名以避免混淆

$stmt = $mysqli->prepare("SELECT object_id FROM ".
      $db_table_prefix."user_events
      WHERE LPAD(start_timestamp,15,'0') < LPAD(?,15,'0')
      AND event_id = ?
      AND EXISTS ( 
        SELECT * FROM ".$db_table_prefix."user_events AS u
          WHERE LPAD(u.start_timestamp,15,'0') > LPAD(?,15,'0')
          AND u.object_id = " .$db_table_prefix.".object_id
          AND u.event_id = ? )
    ");

与其

EXISTS，你可能会发现这里的自连接语法更清晰，我无法从代码中准确推断出您想要的内容，但要为在特定时间之前开始的事件获取object_id，并且稍后也会再次启动：

SELECT  ue1.object_id 
FROM    user_events ue1 join user_events ue2
WHERE   ue1.event_id = ue2.event_id AND
        ue1.object_id = ue2.object_id AND
        ue1.event_id = ? AND 
        LPAD(ue1.start_timestamp, 15, '0') < LPAD(ue2.start_timestamp, 15, '0') AND 
        LPAD(ue1.start_timestamp, 15, '0') < LPAD(?, 15, '0')

并object_id (object_id从 ...