Simplified Order Of Operations

Kevin Feasel

2016-07-22

T-SQL

Michael J. Swart looks at how SQL Server implements order of operations:

I have a book on my shelf called Practical C Programming published by O’Reilly (the cow book) by Steve Oualline. I still love it today because although I don’t code in C any longer, the book remains a great example of good technical writing.

That book has some relevance to SQL today. Instead of memorizing the full list of operators and their precedence, Steve gives a practical subset:

    1. * (Multiply), / (Division)
    2. + (Add), – (Subtract)

Put parentheses around everything else.

Parentheses, even when unnecessary, are usually a good idea.  They help the reader understand what was going through your mind at the time.

Related Posts

Enabling Database-Level Change Tracking

Tim Weigel continues a series on change tracking: If you don’t provide a retention period, SQL Server’s default is 2 days. Auto-cleanup defaults to ON unless you tell it otherwise. Easy! The table level commands aren’t any more complicated. Before we get started, please note that change tracking requires a primary key on the table […]

Read More

Isolation Levels and Dynamic SQL

Max Vernon points out how transaction isolation levels work when combined with sp_executesql: Imagine you have a piece of code where you don’t care about the downsides to the “read uncommitted” isolation level, and do your due diligence by adding SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED; at the start of your code. The code following that statement […]

Read More

Categories

July 2016
MTWTFSS
« Jun Aug »
 123
45678910
11121314151617
18192021222324
25262728293031