我有两个不同的表,其架构如下:
表1:
COLUMN_NAME COLUMN_TYPE
campaign_id varchar(50)
subscriber_id varchar(50)
message varchar(21000)
log_time datetime
log_type varchar(50)
level varchar(50)
campaign_name varchar(500)
表2:
COLUMN_NAME COLUMN_TYPE
guid varchar(100)
sid varchar(100)
url varchar(2500)
ip varchar(20)
is_new varchar(20)
ref varchar(2500)
user_agent varchar(255)
stats_time datetime
country varchar(50)
region varchar(50)
city varchar(50)
city_lat_long varchar(50)
email varchar(100)
我需要一个表,它是这两个表(不是所有列)的合并,并且行应根据时间排序(即表1中的log_time和表2中的stats_time)。这两个表之间没有关系。
我需要从 Table1 中获取的列是
campaign_id
subscriber_id
message
log_time
log_type
campaign_name
表2中我需要的列是:
url
stats_time
email
我可以获得更优化的解决方案吗?
查询:
SELECT url, ip, stats_time, email, campaign_id, subscriber_id, campaign_name, log_time, log_type, time from
(
( SELECT url,ip,stats_time,email,NULL AS campaign_id,NULL AS subscriber_id ,NULL AS campaign_name,NULL AS log_time,NULL AS log_type, NULL AS message, UNIX_TIMESTAMP(stats_time) AS time FROM Tabel2 AS Table2Alias WHERE URL !='' AND EMAIL != '') Order by stats_time desc Limit 100
UNION ALL
( SELECT NULL AS url,NULL AS ip,NULL AS stats_time,NULL AS email,campaign_id,subscriber_id,campaign_name,log_time,log_type,message,UNIX_TIMESTAMP(log_time) AS time FROM Table1 AS Table1Alias WHERE (log_type='x1' OR log_type='x2' OR log_type='x3' OR log_type='x4') order by log_time desc Limit 100)
)
as ResultTable order by time desc
最佳答案
从每个表中选择顶部的Limit + Offset
记录,对结果进行 UNION,然后从 UNION 中进行选择。
因此,如果用户正在查看第 5 页,并且每页有 20 个项目,您将从每个表中选择前 100 个项目,执行 UNION,然后从结果中选择 20 条记录。
关于mysql - 如何从两个不同的、不相关的表中获取最新行,并将它们合并到一个结果集中?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/28110102/