选择不可用的列

Question

I am creating a PHP script and wanted to get the result with the same select query.

Let me explain it for some tables one column is not present so I have created a query to search if the column is present or not.

id={1,2,3,4,5};
$val=select (case when exists (select * from information_schema.columns where table_name='X{id}' and TABLE_SCHEMA='employee' and column_name='EmpID' ) then 1 else 0  end)

//checking if the column EmpID is present or not

if($val==0)
select emp_name,age,address,'EmpID' from employee.X{id};
elseif($val==1)
select emp_name,age,address,EmpID from employee.X{id};

Currently if $val=1, then the output is coming properly.

If $val=0, I wanted to display EmpID as blank(I know that field is not present for that table)

I am passing these values to run another ETL process, so I wanted the data to be passed in same format all the time. That's the reason I wanted the EmpID to be blank

Please help me with this.