drop table if exists foo;

create table foo (
  name varchar(255),
  val  double,
  width double
);

insert into foo
  values ('one', 30, 4),
         ('two', 20, 10),
         ('three', 50, 30),
         ('four', 25, 5),
         ('five', 40, 10);

plot 
  xlabels, swath, transparent light butter swath
  with 
    scale y 0 100 25
    comment ""
    comment left "   Use SWATH to vary line width"
    gridlines
select
  name, val - width/2, val + width/2
  from foo;