表之间的汇总行数差异

Question

我有两个 MySQL tables A 和 B 都具有此模式

ID	entity_id	asset	asset_type
0	12345	x	1
..	.........	.....	..........

我想获得两个 table 之间行数差异最大的聚合前 10/50/任何 entity_ids。我认为我可以通过 entity_id 获得最高行数来手动完成此操作

select count(*), entity_id
-> from A
-> group by entity_id
-> order by count(*) desc;

并且只是手动比较 table B 的相同查询，但我想知道是否有一种方法可以在一个查询中执行此操作，比较每个不同 entity_id 和聚合行计数之间的差异。一些注意事项

entity_id 上有一个索引 tables
Table B 对于每个 entity_id

示例输出

entity_id	difference
12345	100
3232	75
5992	40
and so on	for top 10/50

Answer 1

在每个 table 中聚合并加入结果以获得差异：

SELECT a.entity_id, b.counter - a.counter diff
FROM (SELECT entity_id, COUNT(*) counter FROM A GROUP BY entity_id) a
INNER JOIN (SELECT entity_id, COUNT(*) counter FROM B GROUP BY entity_id) b
ON a.entity_id = b.entity_id
ORDER BY diff DESC LIMIT 10

表之间的汇总行数差异

Aggregated row count differences between tables

mysql

sql

join

count

aggregate-functions