Microsoft introduced the APPLY operator in SQL Server 2005. This under-used, non-standard operator can help us solve a number of common (and not-so-common) problems with elegant code which performs well. We will look several problem spaces in which the APPLY operator shines, such as joining to table-valued functions, getting the top N child records for each parent record, string splitting, and word matching. With the use of these examples, we will gain a deeper understanding of when to use the APPLY operator.
On October 14, 2015, Carlos L. Chacon interviewed me for his SQL Data Partners podcast. You can get the recording and show notes on the SQL Data Partners podcast website.
The slides are licensed under Creative Commons Attribution-ShareAlike.
The source code is licensed under the terms offered by the GPL.