PARTITION BY Clause

PARTITION BY Clause

The PARTITION BY clause is used with SQL analytical functions ANALYTICAL FUNCTIONS. It does this by independently splitting up the obtained result set into separate partitions passed to the analytical function. In this case, the function gets computed differently between partitions, and therefore you can perform a more detailed analysis within the subset of data as well...

GROUP BY Clause

The SQL GROUP BY clause is utilized for performing data aggregation according to the predetermined columns. It clarifies rows that feature the same values in specified columns into summary rows. This means that calculations like SUM, COUNT, AVG, MAX, and MIN can be executed separately for each group of data....

Examples of PARTITION BY and GROUP BY in PL/SQL

Set up an environment:...

Difference Between PARTITION BY and GROUP BY in PL/SQL

Aspect PARTITION BY GROUP BY Functionality Splits the result set into partitions for window functions Groups rows based on common values for aggregate functions Scope Operates within the context of window functions Applies to the entire result set Usage Typically used with analytical/window functions Used with aggregate functions Result Set Partitions the result set, retaining all rows Reduces the result set to summary rows Aggregation Computes separate calculations for each partition Computes aggregate functions for each group Retained Rows Retains all rows in the result set Reduces rows to summary rows Example SUM(sales) OVER (PARTITION BY region) SELECT region, SUM(sales) FROM table GROUP BY region...

Conclusion

Knowing two PL/SQL keywords, “GROUP BY” and “PARTITION BY“, will make it possible for more productive data management and analysis. “GROUP BY” collects data into groups and generally calculates aggregate values, while “PARTITION BY” divides data into partitions and conducts calculations within each partition. Having known these concepts, one becomes able to write SQL queries that are optimized regarding data processing and analysis....