over(partition by …)

Apache DerbyBigQueryDb2 (LUW)H2MariaDBMySQLOracle DBPostgreSQLSQL ServerSQLite20072009201120132015201720192021✓ 3.25.0 - 3.43.0⊘ 3.5.7 - 3.23.1✓ 2008R2 - 2022✓ 8.4 - 16⊘ 8.3✓ 11gR1 - 21c✓ 8.0.11 - 8.0.34⊘ 5.0 - 5.7✓ 10.2 - 10.11⊘ 5.1 - 10.1✓ 1.4.198 - 2.2.220⊘ 1.4.191 - 1.4.197✓ 9.7 - 11.5.8✓ 2.0⊘ -

The over accepts the optional partition by clause to limit the scope of the window function to those rows that have the “same” values in the listed expressions.

  FROM …

Returns the original result with an additional column stating how many rows the result has with the “same“ values in c1 and c2 as the current row.

In this context, “same” means is not distinct from, which treats two null values as indistinguishable (very much like group by does).

Normative References

The over clause, including partition by, is defined in ISO/IEC 9075-2:2023 as part of optional feature T611, “Elementary OLAP operations”.

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