项目的平均响应时间

Question

Its a very basic question, and I am just confused.

Response Time | Item
    2           1
    3           1
    4           1
    1           1 
    4           2 
    4           2 
    4           2
    8           2
    1           3

If column A is the number of days takes by each item (column B) . What is the average response time of each item in column B and the total average response time.

Answer 1

should be easy like:

SELECT Item
      ,SUM(ResponseTime) AS Total_ResponseTime
      ,AVG(ResponseTime) AS Average_ResponseTime
      ,(SELECT AVG(ResponseTime) FROM mytab) as Total_Average_ResponseTime
  FROM yourtable
GROUP BY Item

If you wanna reproduce my result, you can use this link: http://rextester.com/LIV1334

Answer 2

is this what you're looking for?

select item, avg([respone time]) 
from items
group by item

Answer 3

Something like this:

SELECT item, AVG(response_time)
FROM table
GROUP BY item

Answer 4

This is pretty straight forward aggregation. https://docs.microsoft.com/en-us/sql/t-sql/functions/avg-transact-sql

select AVG(ResponseTime)
    , Item
from YourTable
group by Item