The jOOQ User Manual SQL building Column expressions Window functions ORDER BY

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ORDER BY

Applies to ✅ Open Source Edition   ✅ Express Edition   ✅ Professional Edition   ✅ Enterprise Edition

The ORDER BY clause allows for ordering a window, which may be required by a window function to produce a deterministic result.

There are 2 reasons to order window functions:

• The window function requires it (e.g. ROW_NUMBER).
• The window has a explicit or implicit window frame.

While the window frame ordering will be discussed later, it is easy to see how ROW_NUMBER relies on ordering in an example:

SELECT
  BOOK.ID,
  row_number() OVER (ORDER BY id DESC)
FROM
  BOOK

create.select(
         BOOK.ID,
         rowNumber().over(orderBy(BOOK.ID.desc())))
      .from(BOOK)
      .fetch();

Producing:

+----+------------+
| id | row_number |
+----+------------+
|  1 |          4 |
|  2 |          3 |
|  3 |          2 |
|  4 |          1 |
+----+------------+

Dialect support

This example using jOOQ:

rowNumber().over(orderBy(BOOK.ID))

Translates to the following dialect specific expressions:

Aurora Postgres, BigQuery, ClickHouse, CockroachDB, DB2, DuckDB, Exasol, Firebird, H2, Hana, Informix, MariaDB, MemSQL, MySQL, Oracle, Postgres, Redshift, SQLDataWarehouse, SQLServer, SQLite, Snowflake, Sybase, Teradata, Trino, Vertica, YugabyteDB

row_number() OVER (ORDER BY BOOK.ID)

ASE, Access, Aurora MySQL, Derby, HSQLDB

/* UNSUPPORTED */

The jOOQ User Manual SQL building Column expressions Window functions ORDER BY

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