@vsr, your task is different from @shiro's task. @shiro needed to fit a spline by different values of one column.
Look at the example I provided, the curve shown is is different for different values of :State.
From your description, you seem to want different columns, not different values of one column. Fit Where is selecting on values of a chosen column. Without more details of what specifically you are trying to do, I can only guess.
My guess is that you might want to plot different Y's or different X's, that is columns. If that is teh case JMP has a builtin solution, called a column switcher. Just in case, that is what you are needing, I provided an example screenshot and script. If this is not what you need, please provide more details.
Names Default to Here(1);
dt = Open("$sample_data/TechStock.jmp");
biv = dt << Bivariate(
Y( :Name( "Adj. Close*" ) ),
X( :Date ),
Fit Spline( 10, {Line Color( {212, 73, 88} )} ),
Column Switcher(
:Name( "Adj. Close*" ),
{:Open, :High, :Low, :Close, :Name( "Adj. Close*" )}
)
);
//select a Y column one at a time or select the "play/go" button and JMP will cycle thru all columns