Many of the early sewing machines were powered by a treadle mechanism. The treadle was operated by pressing down on it with a foot, or both feet, to cause a rocking movement. This movement spins a large wheel on the treadle frame, connected by a thin leather belt to a smaller driving wheels on the sewing machine.
null. adj. 1. Having no legal force; invalid: render a contract null and void.2.ull. adj. 1. Having no legal force; invalid: render a contract null and void. 2.
The NVL function allows you to replace null values with a default value. If the value in the first parameter is null, the function returns the value in the second parameter. If the first parameter is any value other than null, it is returned unchanged. We know that COL1 in the test table contains null in all rows except the first.