COALESCE Tag Archives

Learn How to Combine Data with a CROSS JOIN

Cross Join Meme

A cross join is used when you wish to create combination of every row from two tables.  All row combinations are included in the result; this is commonly called cross product join.  A common use for a cross join is to create obtain all combinations of items, such as colors and sizes. Note:  The series […]

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What is a Database NULL Value?

Null and unknown values

What is a Null Value? In databases a common issue is what value or placeholder do you use to represent a missing values.   In SQL, this is solved with null.  It is used to signify missing or unknown values.  The keyword NULL is used to indicate these values.  NULL really isn’t a specific value as much as it […]

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