Yes, Day of the Dead is celebrated in Chile. Though it is not a  time to necessarily dress up in a skeleton costume and party-it  is a much more somber holiday. Most busin â¦ esses will be closes and  many people will be at the cemeteries. Not in a sad way either, but  in a happy one.
NULL Statement The NULL statement is a no-op (no operation); it passes control to the next statement without doing anything. In the body of an IF-THEN clause, a loop, or a procedure, the NULL statement serves as a placeholder. For more information, see Using the NULL Statement. Syntax
If that's true, then it's a pk violation and the insert fails. But that doesn't work for NULL, because NULL = NULL is not true in SQL. Some databases (for example, MySQL) allow nullable columns with a UNIQUE constraint, but then it allows any number of rows to have .