数据库表计数相同的值 [英] Database table count same value

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

试试这个：

Try this:

SELECT refer_id, COUNT(refer_id) AS CountOfReferId
FROM YourTable
GROUP BY refer_id
ORDER BY refer_id

更多关于：聚合函数 - MySQL 5.0参考 [ ^ ]

MySQL集合函数 [ ^ ]



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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