SQL Lion

For proper analyzing of data, sometimes we need to group them under certain categories.  These categories are defined under some constraints over the data. For this GROUP BY Clause is very useful.

GROUP BY Clause is used with SELECT Command, and specifies the groups into which output rows are to be placed by the values of one or more columns or expressions.  And if aggregated functions are used in the SELECT statements, then GROUP BY clause computes a summary value for each group.

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