The Basics of Good T-SQL Coding Style – Part 4: Performance

There are several obvious problems with poor SQL Coding habits. It can make code difficult to maintain, or can confuse your team colleagues. It can make refactoring a chore or make testing difficult. The most serious problem is poor performance. You can write SQL that looks beautiful but performs sluggishly, or interferes with other threads. A busy database developer adopts good habits so as to avoid staring at execution plans. Rob Sheldon gives some examples.

Logical Query Processing Filters

Compressing Integers

When sp_HelpText is not so helpful!

A note of caution on the use of sp_helptext to script out objects.

More Order of Processing

Saving Master Keys

Calculating the Tally

Creating a large database

SQL Data Aggregation Aggravation

When we have to deal with and store a lot of data, it makes sense to aggregate it so that we store only the information we actually need. If we get this right, this works well, but the design of the system takes care and thought because the problems can be subtle and various. Joe Celko describes some of the ways that things can go wrong and end up providing incorrect, inaccurate or misleading results.

Temporary tables SCOPE