在 SQL 查询中一起选择列和最后一列的值的总和

Question

I have a table named results where I have id(pk) and marks. I want to develop a select query to get the sum(marks) and also the highest individual marks in a single query. Is it possible?

sample data:

• id ---- marks
• 1 ---- 50
• 2 ---- 60
• 3 ---- 70
• 4 ---- 44

Expected output: Sum(224), last_marks(44)

I have tried the following way:

SELECT SUM(marks), latest.marks
FROM results
JOIN ( SELECT marks FROM results ORDER BY id DESC LIMIT 1) as latest;

It shows error as follows: Error Code: 1052. Column 'marks' in field list is ambiguous

Answer 1

You can get result using seperate queries and merging results using UNION .

SELECT SUM(marks) AS marks_sum FROM results
UNION
SELECT marks AS latest_marks  FROM results WHERE id=(SELECT MAX(id) FROM results)

OR if need results in one row use query in query:

SELECT (SELECT SUM(marks) FROM results) AS marks_sum,
(SELECT marks FROM results WHERE id=(SELECT MAX(id) FROM results)) AS latest_marks