SQL 服务器：具有相同 ID 的 SUM 列

Question

I am new to SQL and experimenting with a database of baseball stats. I would like to write a query that displays the total hits by each player over their career. I know how to SUM the hits of an individual player using:

Select Sum(H) 
From Batting 
Where PlayerID = 'aaronha01'

Result = 3771

but I can not figure out how to query every player at once. I would like the result of my query to look something like this:

|PlayerID|, |Hits|  
|player 1|, |3771|  
|player 2|, |5562|  
etc...  

Any help would be greatly appreciated. I have included a screenshot of the table if it that provides help to you.

Answer 1

You have to use the GROUP BY clause to sum the hits per every group of battings (the PlayerID)

Select PlayerID, Sum(H) as Hits
From Batting 
Group By PlayerID

Answer 2

Select playerID, sum(H) Hits From Batting Group By playerID

Answer 3

SUM is used with a GROUP BY clause.

The aggregate functions summarize the table data. Once the rows are divided into groups, the aggregate functions are applied in order to return just one value per group. It is better to identify each summary row by including the GROUP BY clause in the query resulst. All columns other than those listed in the GROUP BY clause must have an aggregate function applied to them.

SELECT PlayerID, SUM(H) AS 'Hits' FROM Batting GROUP BY PlayerID