The DIALOG statement builds a WHERE command. The arguments for the WHERE
command are provided by user input into the text entry fields described by
the three TEXT statements. The @1 notation is a placeholder for user input
in the text field. The TEXT statements specify the text in the dialog box
and the length of the input field.
dialog d1 'where @1';
text #2 @3 'Enter a valid WHERE clause or UNDO';
text #4 @3 'WHERE ';
text #4 @10 len=40;
quit;