如何通过分组从内部联接中选择计数?
SELECT COUNT(table1.act) FROM table1
INNER JOIN table2 ON table1.act = table2.act
GROUP BY table1.act
这将返回表2中的行为计数。
添加
SELECT table1.act, COUNT(table1.act) AS test
返回
act test
------- ----
17682 3
17679 3
17677 3
11636 1
11505 1
我想收到已发现的行为总数。
所以我想得到5.你能帮忙吗?
答案 0 :(得分:20)
您可以将该查询包装到另一个查询中:
SELECT COUNT(*) FROM (
SELECT COUNT(table1.act) AS actCount FROM table1
INNER JOIN table2 ON table1.act = table2.act
GROUP BY table1.act
) t
答案 1 :(得分:3)
SELECT COUNT(distinct table1.act) FROM table1
INNER JOIN table2 ON table1.act = table2.act
答案 2 :(得分:0)
SELECT COUNT(table2.act) FROM table1
INNER JOIN table2 ON table1.act = table2.act
答案 3 :(得分:0)
如果您只想要结果计数,
SELECT COUNT(1)
FROM table1
INNER JOIN table2 ON table1.act = table2.act
GROUP BY table1.act
应该给你