How to update single column based on conditions : How to update single column based on two or multiple conditions in mssql.
I have table called show_list and it looks like

    emp_id     to_date      show_flag
    1	      2019-01-01			
    2         2019-01-01
    3         2019-01-01
    4	      2019-01-01

I have to update emp_id 1 and 3 with show_flag = 1 and emp_id 2 and 4 with show_flag = 0.