Sorting in sql server by two columns : I've an employee table with below details 

EMPid      TimeIn.                    TimeOut
123           1 Jan 2016 10:10   NULL
123           NULL                1 Jan 2016 18:30
123           1 Jan 2016 9:10     NULL
123           NULL               1 Jan 2016 18:00

I need output with order by time in ascending order. Below is sample output. 

EMPid      TimeIn.                    TimeOut
123           1 Jan 2016 9:10      NULL
123           1 Jan 2016 10:10    NULL 
123           NULL               1 Jan 2016 18:00
123           NULL               1 Jan 2016 18:30
