An interesting bit operation on SQL server

SQL server does not have the bool type, but uses the bit type to represent the bool value, which is estimated to save storage space.

However, it may be difficult to implement the reverse operation. For example, the following statement cannot be used: update category set visible = not visible where id = 1, because visible is of the bit type, instead of the bool type.

An interesting problem occurred. We found that bit-1 in SQL Server can represent 1, so we can change the preceding statement:

Update category set visible = visible-1 where id = 1

Haha: Of course, you can also write it like this: update category set visible = 1-visible where id = 1, so there is no-1, and there is only 0 and 1.