如何左连接多个表，以显示最新维护工单完成日期？

使用LEFT JOIN关键字来左连接多个表，并使用子查询和MAX函数来检索最新的维护工单完成日期。以下是一个示例代码：

SELECT t1.id, t2.ticket_completion_date, t3.ticket_completion_date, t4.ticket_completion_date FROM table1 t1 LEFT JOIN ( SELECT id, MAX(completion_date) AS ticket_completion_date FROM table2 GROUP BY id ) t2 ON t1.id = t2.id LEFT JOIN ( SELECT id, MAX(completion_date) AS ticket_completion_date FROM table3 GROUP BY id ) t3 ON t1.id = t3.id LEFT JOIN ( SELECT id, MAX(completion_date) AS ticket_completion_date FROM table4 GROUP BY id ) t4 ON t1.id = t4.id;