Arithmetic With NULL

Kevin Feasel

2016-04-27

T-SQL

Kennie Nybo Pontoppidan looks at how NULL values complicate arithmetic operations:

If NULL is used in an in-row expression, the full expression will be NULL. This makes sense for most arithmetic operations, because NULL means unknown.

Here is an example with NULL plus/minus ONE:

There’s a consistency to NULL operations, but it’s sometimes a weird consistency.

Related Posts

Debugging a Pivot

Ed Elliott takes us through problems with the PIVOT statement: If you have a PIVOT query and it isn’t returning the data you expect, what can you do to troubleshoot it? The thing to do is to break it down into the constituent parts. First, lets take a look at a query and see what […]

Read More

Avoiding DONE Tokens in Loops

Emanuele Meazzo shows one reason why loops can be so much slower in T-SQL: Not everybody knows that SQL Server sends a DONE Token to the client each time that a SQL statement completes (so, everything except variable declarations); For the query above you can basically track it with extended events by tracking the “SQL Statement Completed” […]

Read More

Categories

April 2016
MTWTFSS
« Mar May »
 123
45678910
11121314151617
18192021222324
252627282930