我想从不同的列添加值

Question

我有一张名为leave的表：

leave_id    employee_id dateApplied leaveStrtDate   leaveEndDate    no_of_days  
3              1              2012-10-31    2012-10-10  2012-10-17        5     
4              1              2012-10-31    2012-10-24  2012-10-17       10 

现在我想使用mysql查询从no_of_days列添加值，例如：no_of_days的总和应为15.有没有办法在mysql查询中执行此操作？

Answer 1

SELECT  employeeID, sum(no_of_days)  totalDays
FROM    leave
GROUP BY employeeID

Answer 2

select sum(no_of_days) from leave

Answer 3

SELECT SUM(no_of_days) FROM leave;

您可以使用mysql sum函数

Answer 4

select sum(no_of_days) from leave group by employee_id;

这将在休假表中获得每位员工的休假天数。

Answer 5

Select SUM(no_of_days) from leave;

Document for sum ()