目的:sql客户端中,统计多表数据,并以不同字段方式展示;
举例:
当前库中存在表block / element / file / md5 / segment / target 6个表;
分别统计6个表的数据数量,并以表名称作为字段展示查询结果
语句:
SELECT * from
(SELECT COUNT(1) as 'file' from file) a
left join
(SELECT COUNT(1) as 'element' from element) b
left join
(SELECT COUNT(1) as 'block' from block) c
left join
(SELECT COUNT(1) as 'segment' from segment) d
left join
(SELECT COUNT(1) as 'target' from target) e
left join
(SELECT COUNT(1) as 'md5' from md5) f
结果: