Available in versions: Dev (3.19) | Latest (3.18) | 3.17 | 3.16 | 3.15 | 3.14 | 3.13 | 3.12 | 3.11 | 3.10 | 3.9
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 | +----+------------+
If you omit the ORDER BY clause (and if that's supported in a window function), then no frame clause is implied, and thus the entire window partition is being considered.
Dialect support
This example using jOOQ:
rowNumber().over(orderBy(BOOK.ID))
Translates to the following dialect specific expressions:
-- AURORA_POSTGRES, BIGQUERY, COCKROACHDB, DB2, DUCKDB, EXASOL, FIREBIRD, H2, HANA, INFORMIX, MARIADB, MEMSQL, MYSQL, -- ORACLE, POSTGRES, REDSHIFT, SNOWFLAKE, SQLDATAWAREHOUSE, SQLITE, SQLSERVER, SYBASE, TERADATA, TRINO, VERTICA, YUGABYTEDB row_number() OVER (ORDER BY BOOK.ID) -- ACCESS, ASE, AURORA_MYSQL, DERBY, HSQLDB /* UNSUPPORTED */
(These are currently generated with jOOQ 3.19, see #10141), or translate your own on our website
Feedback
Do you have any feedback about this page? We'd love to hear it!