TSQL，计算表中的值对

Question

给出格式为

的表格

ID   Forename    Surname
1    John        Doe
2    Jane        Doe
3    Bob         Smith
4    John        Doe

你将如何获得输出

Forename  Surname  Count
John      Doe      2
Jane      Doe      1
Bob       Smith    1

对于单个列我只会使用count，但我不确定如何将其应用于多个。

Answer 1

SELECT Forename, Surname, COUNT(*) FROM YourTable GROUP BY Forename, Surname

Answer 2

我认为这应该有效：

SELECT Forename, Surname, COUNT(1) AS Num 
FROM T
GROUP BY Forename, Surname