mysql - 查找至少参与过两个项目的所有员工

Question

表:项目资源

IDPRoject  IDEmployee  NumHours   PricePerHr
1          1876       500        65
1          4354       2000       31
2          2231       250        55
3          2231       500        65
3          1212       3000       35
3          1876       2000       35

我只提出了以下研究语法，但不知道如何过滤以仅指示 2231 和 1876:

SELECT IDEmployee, COUNT (*) AS ‘Number of Projects’
FROM Projectressources
GROUP BY IDEmployee;

Answer 1

您正朝着正确的方向前进。您缺少的部分是 having 子句，它允许您过滤聚合表达式，例如 count(*):

SELECT   IDEmployee, COUNT (*) AS ‘Number of Projects’ 
FROM     Projectressources
GROUP BY IDEmployee
HAVING   COUNT(*) > 1 -- Here!