5.2

Grouping Data

Using the GROUP BY Clause

  • Group rows based on a column(s) or expression(s).
  • If you use an aggregate function with a GROUP BY clause, the aggregation is calculated for each group.

Table 1. GROUP BY Function

Aggregate Function Order of Execution Description

GROUP BY

3

Groups rows of a result set based on columns or expressions separated by commas.

Filtering With WHERE And HAVING

  • Notice the order of execution. GROUP BY happens before WHERE but after HAVING.
  • It is possible to use WHERE and HAVING in the same statement. They are not mutually exclusive.

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