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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