问题描述
我有一个数据库表，其中用户ID具有另一个用户的外国ID，例如：
id | refer_id
1 ....... 98
2 ....... 7
3 .. ..... 4
4 ....... 98
5 ....... 87
6。 ...... 13
7 ....... 4
8 ....... 4
我想查看整个表并计算出有2（98），1（7），3（4），1（13）等等。
我是数据库的新手并且混淆了查询的工作方式。
I have a database table which users id had a foreign id of another user like:
id | refer_id
1.......98
2.......7
3.......4
4.......98
5.......87
6.......13
7.......4
8.......4
I want to check the whole table and count that there''s 2(98),1(7),3(4),1(13) and so on.
I am new to database and confuse how the query going to work.
推荐答案
SELECT refer_id, COUNT(refer_id) AS CountOfReferId
FROM YourTable
GROUP BY refer_id
ORDER BY refer_id
更多关于： []
[]
获取refer_id'的位置 COUNT（ refer_id）> = 4
More about: Aggregate functions - MySQL 5.0 Reference[^]
MySQL aggregate functions[^]
To get refer_id''s where COUNT(refer_id)>=4
SELECT refer_id, COUNT(refer_id)
FROM Table1
GROUP BY refer_id
HAVING COUNT(refer_id)>=4
获取 SUM（上图）
To get SUM(above)
SELECT SUM(T.CountOfReferId) AS SumOfCountReferId_4
FROM (
SELECT refer_id, COUNT(refer_id) AS CountOfReferId
FROM Table1
GROUP BY refer_id) AS T
WHERE T.CountOfReferId >=4
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