带有计算列的SQL查询

Question

请帮我查询一下.假设我们有一个包含列的表:

• 交易
• 开始时间
• 时间结束

现在,我需要一个带有计算列的查询(value = EndTime-Startime).实际上我需要对用户进行分组(Transaction为用户提供FK)并按平均交易时间对其进行排序.

Answer 1

SELECT u.userid
       ,AVG(DATEDIFF(second, StartTime, EndTime) AS AvgTime
FROM trxn AS t
INNER JOIN users AS u
    ON trxn.userid = u.userid
GROUP BY u.userid
ORDER BY AVG(DATEDIFF(second, StartTime, EndTime)