NULL in Oracle

The Null Value in Oracle does not mean anything. Is not null.

For example, in table 1, there is a nub_flag of the number (1) type. Some of the values are already 1, and others are all empty. You want to update other values to 0.

Write a statement update Table1 set nub_flag = 0 where nub_flag <> 1

I think this statement is okay. But the number of results updated is 0. In fact, the null value is not in this range, and is not in the range of = 1.

In fact, the correct statement should be update Table1 set nub_flag = 0 where nub_flag is null;