diff options
| author | Anders Kaseorg <andersk@mit.edu> | 2023-05-29 21:59:22 -0700 |
|---|---|---|
| committer | Mariusz Felisiak <felisiak.mariusz@gmail.com> | 2023-06-08 20:41:18 +0200 |
| commit | b81e974e9ea16bd693b194a728f77fb825ec8e54 (patch) | |
| tree | e0c816bf6751563791235ae95402e43af1acf6b1 /docs | |
| parent | ee36e101e8f8c0acde4bb148b738ab7034e902a0 (diff) | |
Fixed #34604 -- Corrected fallback SQL for n-ary logical XOR.
An n-ary logical XOR Q(…) ^ Q(…) ^ … ^ Q(…) should evaluate to true
when an odd number of its operands evaluate to true, not when exactly
one operand evaluates to true.
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/ref/models/querysets.txt | 15 | ||||
| -rw-r--r-- | docs/releases/5.0.txt | 5 |
2 files changed, 17 insertions, 3 deletions
diff --git a/docs/ref/models/querysets.txt b/docs/ref/models/querysets.txt index 1d684607f1..640818d2a5 100644 --- a/docs/ref/models/querysets.txt +++ b/docs/ref/models/querysets.txt @@ -2021,7 +2021,8 @@ may be generated. XOR (``^``) ~~~~~~~~~~~ -Combines two ``QuerySet``\s using the SQL ``XOR`` operator. +Combines two ``QuerySet``\s using the SQL ``XOR`` operator. A ``XOR`` +expression matches rows that are matched by an odd number of operands. The following are equivalent:: @@ -2044,13 +2045,21 @@ SQL equivalent: .. code-block:: sql (x OR y OR ... OR z) AND - 1=( + 1=MOD( (CASE WHEN x THEN 1 ELSE 0 END) + (CASE WHEN y THEN 1 ELSE 0 END) + ... - (CASE WHEN z THEN 1 ELSE 0 END) + + (CASE WHEN z THEN 1 ELSE 0 END), + 2 ) + .. versionchanged:: 5.0 + + In older versions, on databases without native support for the SQL + ``XOR`` operator, ``XOR`` returned rows that were matched by exactly + one operand. The previous behavior was not consistent with MySQL, + MariaDB, and Python behavior. + Methods that do not return ``QuerySet``\s ----------------------------------------- diff --git a/docs/releases/5.0.txt b/docs/releases/5.0.txt index 98bd5d2a9f..fb446fcd7a 100644 --- a/docs/releases/5.0.txt +++ b/docs/releases/5.0.txt @@ -424,6 +424,11 @@ Miscellaneous a page. Having two ``<h1>`` elements was confusing and the site header wasn't helpful as it is repeated on all pages. +* On databases without native support for the SQL ``XOR`` operator, ``^`` as + the exclusive or (``XOR``) operator now returns rows that are matched by an + odd number of operands rather than exactly one operand. This is consistent + with the behavior of MySQL, MariaDB, and Python. + .. _deprecated-features-5.0: Features deprecated in 5.0 |