Relational databases store information in tables — columns that are analogous to elements in a data structure and rows which are one instance of that data structure. In those cases where this data set contains duplicate values (like membership location by state or province) SQL Distinct traverses these data, filters them, and returns just one of each duplicated value (making it easy to determine, for example, the number of members living in each state). SQL Distinct evaluates the span of a particular set of values.
Starting With SQL Distinct
We start with a table of some of Charles Dickens’ characters and the novels in which they appear. This table is imagined not as an exhaustive index of every character but those most worth discovering; it’s a table of the most notable and memorable characters in Dickens’ oeuvre.
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