sql-多个表选择最后一个值名称

Question

我在mariadb数据库中有五个表，我想选择每个名称表的最后一个值，

我执行此sql命令以获取主机，名称和严重性，

我尝试了这个sql命令：

select host, e.name, e.severity
from hosts
left join items i on (i.hostid = hosts.hostid)
inner join functions f on (f.itemid = i.itemid)
inner join triggers t on (t.triggerid = f.triggerid)
INNER JOIN events e ON (e.objectid = t.triggerid)
group by hosts.hostid;

我想要最后一个主机，名称和严重性， 我想要这个结果在sql中：

Answer 1

我以triggerid在triggers表中递增的假设来回答这个问题

select host, e.name, e.severity
from hosts
left join items i on (i.hostid = hosts.hostid)
inner join functions f on (f.itemid = i.itemid)
inner join triggers t on (t.triggerid = f.triggerid)
INNER JOIN events e ON (e.objectid = t.triggerid)
where t.triggerid = (select max(t.triggerid) from triggers)