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Minor edits to Greatest/Least docs; refs #24767.

This commit is contained in:
Tim Graham 2015-06-05 11:40:10 -04:00
parent 286d0e6ab1
commit 6b41834855
2 changed files with 13 additions and 15 deletions
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6
django/db/models/functions.py
View File

@ -89,8 +89,7 @@ class Greatest(Func):
If any expression is null the return value is database-specific: If any expression is null the return value is database-specific:
On Postgres, the maximum not-null expression is returned. On Postgres, the maximum not-null expression is returned.
On MySQL, Oracle and SQLite, if any expression is null, null is On MySQL, Oracle, and SQLite, if any expression is null, null is returned.
returned.
""" """
function = 'GREATEST' function = 'GREATEST'
@ -110,8 +109,7 @@ class Least(Func):
If any expression is null the return value is database-specific: If any expression is null the return value is database-specific:
On Postgres, the minimum not-null expression is returned. On Postgres, the minimum not-null expression is returned.
On MySQL, Oracle and SQLite, if any expression is null, null is On MySQL, Oracle, and SQLite, if any expression is null, null is returned.
returned.
""" """
function = 'LEAST' function = 'LEAST'

22
docs/ref/models/database-functions.txt
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@ -96,13 +96,13 @@ Usage example::
Greatest Greatest
-------- --------
.. versionadded:: 1.9
.. class:: Greatest(*expressions, **extra) .. class:: Greatest(*expressions, **extra)
.. versionadded:: 1.9
Accepts a list of at least two field names or expressions and returns the Accepts a list of at least two field names or expressions and returns the
greatest value. Each argument must be of a similar type, so mixing text and numbers greatest value. Each argument must be of a similar type, so mixing text and
will result in a database error. numbers will result in a database error.
Usage example:: Usage example::
@ -121,8 +121,8 @@ Usage example::
>>> comments = Comment.objects.annotate(last_updated=Greatest('modified', 'blog__modified')) >>> comments = Comment.objects.annotate(last_updated=Greatest('modified', 'blog__modified'))
>>> annotated_comment = comments.get() >>> annotated_comment = comments.get()
``annotated_comment.last_updated`` will be the most recent of ``annotated_comment.last_updated`` will be the most recent of ``blog.modified``
``blog.modified`` and ``comment.modified``. and ``comment.modified``.
.. warning:: .. warning::
@ -131,19 +131,19 @@ Usage example::
- PostgreSQL: ``Greatest`` will return the largest non-null expression, - PostgreSQL: ``Greatest`` will return the largest non-null expression,
or ``null`` if all expressions are ``null``. or ``null`` if all expressions are ``null``.
- SQLite, Oracle and MySQL: If any expression is ``null``, ``Greatest`` - SQLite, Oracle, and MySQL: If any expression is ``null``, ``Greatest``
will return ``null``. will return ``null``.
The PostgreSQL behavior can be emulated using ``Coalesce`` if you know The PostgreSQL behavior can be emulated using ``Coalesce`` if you know
a sensible minimum value to provide as a default. a sensible minimum value to provide as a default.
Least Least
-------- -----
.. versionadded:: 1.9
.. class:: Least(*expressions, **extra) .. class:: Least(*expressions, **extra)
.. versionadded:: 1.9
Accepts a list of at least two field names or expressions and returns the Accepts a list of at least two field names or expressions and returns the
least value. Each argument must be of a similar type, so mixing text and numbers least value. Each argument must be of a similar type, so mixing text and numbers
will result in a database error. will result in a database error.
@ -155,7 +155,7 @@ will result in a database error.
- PostgreSQL: ``Least`` will return the smallest non-null expression, - PostgreSQL: ``Least`` will return the smallest non-null expression,
or ``null`` if all expressions are ``null``. or ``null`` if all expressions are ``null``.
- SQLite, Oracle and MySQL: If any expression is ``null``, ``Least`` - SQLite, Oracle, and MySQL: If any expression is ``null``, ``Least``
will return ``null``. will return ``null``.
The PostgreSQL behavior can be emulated using ``Coalesce`` if you know The PostgreSQL behavior can be emulated using ``Coalesce`` if you know