Just using Not(IsMissing()) should be enough
Names Default To Here(1);
dt = New Table("Untitled",
Add Rows(5),
Compress File When Saved(1),
New Column("Column 1",
Numeric,
"Continuous",
Format("Best", 12),
Set Values([., 2, ., 5, .])
)
);
dt << New Column("Check", Numeric, Nominal, Formula(
!IsMissing(:Column 1)
));
And if you want to have then as characters wrap that with Char()
Char(!Is Missing(:Column 1))
-Jarmo