Mysql分组与计数

Question

我有 3 张 table :

1 TableTraders
trader_id|Domain|
---------------------
1|google.com
2|yahoo.com

2 个表 Counter_in

counter_time    counter_ip  counter_domain_id
    111111  222222  1
    111111  222224  2
    111111  222225  3
    111111  222232  2
    111111  222221  3
    111111  222223  4
    1111311     22223422    5



 3 Table Out Counter
counter_time    counter_ip  counter_domain_id
    111111  222222  1
    111111  222222  2
    111111  222222  3
    111111  222226  2
    111111  222221  3
    111111  222222  4
1309351485  2130708581  5
    1309351485  2130708581  4
    1309710116  2130706433  4
    1309351485  2130708581  1
1309710274  2130706433  1

好吧，我想要做的是将表 1 、 2 、 3 连接起来，并将它们分组在一起，然后对它们进行计数。

trader_id|DOMAIN|IN|OUT
--------------------------
1|google.com|3|1
2|yahoo.com|1|2

我尝试了很多方法，但总是得到错误的结果。我如何正确加入查询以获得我想要的结果

*编辑

尝试的查询:

SELECT traders.trader_id, traders.domain, COUNT( counter_in.counter_domain_id ) AS today_in, COUNT( counter_out.counter_domain_id ) AS today_out
FROM traders
JOIN counter_in ON traders.trader_id = counter_in.counter_domain_id
JOIN counter_out ON traders.trader_id = counter_out.counter_domain_id
GROUP BY traders.trader_id, traders.domain
LIMIT 0 , 30

结果:

trader_id   domain  today_in    today_out
1   bing.com    3   3
2   google.com  4   4
3   yahoo.com   4   4
4   msn.com     3   3
5   yandex.com  1   1

Answer 1

SELECT
  TableTraders.trader_id,
  TableTraders.Domain,
  COUNT(TableIn.trader_id) AS in_count,
  COUNT(TableOut.trader_id) AS out_count
FROM TableTraders 
  JOIN TableIn ON TableTraders.trader_id = TableIn.trader_id
  JOIN TableOut ON TableTraders.trader_id = TableOut.trader_id
GROUP BY TableTraders.trader_id, TableTraders.Domain

不确定上面示例中的表名称是什么，因为它们包含空格。替换正确的表名称。