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The Outer Product

Else Logic was originally conceived in support for the outer product, an alternative method for creating outer join queries. This tutorial will explain the outer product and what Else Logic can do for it.

The outer product is just a fancy name for appending an extra empty row after a table. In SQL we can do this using the UNION operator with a SELECT statement containing only NULLs.

The query example: guaranteed result

This code example shows the outer product in plain SQL. The example also illustrates a use cases for the outer product by itself: when you want to find something or return a default value if nothing is found. Guaranteed result seems a good name. That Else Logic is of use here is a pure coincidence of course.

"show me the people with 'xx' in their name 
   or 
 return a row stating that nothing was found"

Also it is a nice introduction to one of the new example tables we will be using in this tutorial. To trigger the default try it something like "yy" instead of "xx".




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