>x='qq' >x=null >?type('x') && C >This is not a wrong result. X was previously defined to be character. When a NULL value is populated into X it is a NULL Character. The same holds true if you use x=10 and x=null. It now reports a NULL Numeric. It is reporting exactly the type of variable it is ... it's just that now instead of being populated with data, it is populated with empty data (a null).
x = 10 x = null @ 5,5 get x READIt initially shows ".NULL." but when you try to type input, it only allows numbers. If the user types anything (even the letter "k") the value changes to 0. If the user doesn't type anything in that field then it remains NULL.