What Is a UNION?
A UNION lets you select the rows from two or more similar result sets and combine them into a single result set. Notice that we said “rows,” not “columns.” In Chapters 8 and 9, you learned how to bring together columns from two or more result sets using a JOIN. When you ask for a JOIN, the columns from the result sets appear side by side. For example, if you ask for the RecipeClassDescription from the Recipe_Classes table and the RecipeTitle from the Recipes table with a JOIN, you get a result set that looks like Figure 10-1.
Figure 10-1. Fetching data from two tables using a JOIN
Let’s first take a quick look at the syntax ...
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