Fixed #28649 -- Added ExtractIsoYear database function and iso_year lookup.

6 files changed, 30 insertions, 5 deletions

diff --git a/django/db/backends/mysql/operations.py b/django/db/backends/mysql/operations.py
index babf522e45..877c32b6a7 100644
--- a/django/db/backends/mysql/operations.py
+++ b/django/db/backends/mysql/operations.py
@@ -42,6 +42,10 @@ class DatabaseOperations(BaseDatabaseOperations):
             # other database backends.
             # Mode 3: Monday, 1-53, with 4 or more days this year.
             return "WEEK(%s, 3)" % field_name
+        elif lookup_type == 'iso_year':
+            # Get the year part from the YEARWEEK function, which returns a
+            # number as year * 100 + week.
+            return "TRUNCATE(YEARWEEK(%s, 3), -2) / 100" % field_name
         else:
             # EXTRACT returns 1-53 based on ISO-8601 for the week number.
             return "EXTRACT(%s FROM %s)" % (lookup_type.upper(), field_name)
diff --git a/django/db/backends/oracle/operations.py b/django/db/backends/oracle/operations.py
index 62830476bf..7018123cfa 100644
--- a/django/db/backends/oracle/operations.py
+++ b/django/db/backends/oracle/operations.py
@@ -69,6 +69,8 @@ END;
             return "TO_CHAR(%s, 'IW')" % field_name
         elif lookup_type == 'quarter':
             return "TO_CHAR(%s, 'Q')" % field_name
+        elif lookup_type == 'iso_year':
+            return "TO_CHAR(%s, 'IYYY')" % field_name
         else:
             # https://docs.oracle.com/database/121/SQLRF/functions067.htm#SQLRF00639
             return "EXTRACT(%s FROM %s)" % (lookup_type.upper(), field_name)
diff --git a/django/db/backends/postgresql/operations.py b/django/db/backends/postgresql/operations.py
index f4e9571f81..b1b83861c1 100644
--- a/django/db/backends/postgresql/operations.py
+++ b/django/db/backends/postgresql/operations.py
@@ -31,6 +31,8 @@ class DatabaseOperations(BaseDatabaseOperations):
         if lookup_type == 'week_day':
             # For consistency across backends, we return Sunday=1, Saturday=7.
             return "EXTRACT('dow' FROM %s) + 1" % field_name
+        elif lookup_type == 'iso_year':
+            return "EXTRACT('isoyear' FROM %s)" % field_name
         else:
             return "EXTRACT('%s' FROM %s)" % (lookup_type, field_name)
 
diff --git a/django/db/backends/sqlite3/base.py b/django/db/backends/sqlite3/base.py
index 20905c83b8..d124fcd47b 100644
--- a/django/db/backends/sqlite3/base.py
+++ b/django/db/backends/sqlite3/base.py
@@ -338,6 +338,8 @@ def _sqlite_date_extract(lookup_type, dt):
         return dt.isocalendar()[1]
     elif lookup_type == 'quarter':
         return math.ceil(dt.month / 3)
+    elif lookup_type == 'iso_year':
+        return dt.isocalendar()[0]
     else:
         return getattr(dt, lookup_type)
 
@@ -410,6 +412,8 @@ def _sqlite_datetime_extract(lookup_type, dt, tzname):
         return dt.isocalendar()[1]
     elif lookup_type == 'quarter':
         return math.ceil(dt.month / 3)
+    elif lookup_type == 'iso_year':
+        return dt.isocalendar()[0]
     else:
         return getattr(dt, lookup_type)
 
diff --git a/django/db/models/functions/__init__.py b/django/db/models/functions/__init__.py
index 5f5a8bd1dc..f005546eb0 100644
--- a/django/db/models/functions/__init__.py
+++ b/django/db/models/functions/__init__.py
@@ -1,9 +1,9 @@
 from .comparison import Cast, Coalesce, Greatest, Least
 from .datetime import (
-    Extract, ExtractDay, ExtractHour, ExtractMinute, ExtractMonth,
-    ExtractQuarter, ExtractSecond, ExtractWeek, ExtractWeekDay, ExtractYear,
-    Now, Trunc, TruncDate, TruncDay, TruncHour, TruncMinute, TruncMonth,
-    TruncQuarter, TruncSecond, TruncTime, TruncWeek, TruncYear,
+    Extract, ExtractDay, ExtractHour, ExtractIsoYear, ExtractMinute,
+    ExtractMonth, ExtractQuarter, ExtractSecond, ExtractWeek, ExtractWeekDay,
+    ExtractYear, Now, Trunc, TruncDate, TruncDay, TruncHour, TruncMinute,
+    TruncMonth, TruncQuarter, TruncSecond, TruncTime, TruncWeek, TruncYear,
 )
 from .math import (
     Abs, ACos, ASin, ATan, ATan2, Ceil, Cos, Cot, Degrees, Exp, Floor, Ln, Log,
@@ -24,7 +24,8 @@ __all__ = [
     # datetime
     'Extract', 'ExtractDay', 'ExtractHour', 'ExtractMinute', 'ExtractMonth',
     'ExtractQuarter', 'ExtractSecond', 'ExtractWeek', 'ExtractWeekDay',
-    'ExtractYear', 'Now', 'Trunc', 'TruncDate', 'TruncDay', 'TruncHour',
+    'ExtractIsoYear', 'ExtractYear', 'Now', 'Trunc', 'TruncDate', 'TruncDay',
+    'TruncHour', 'TruncMinute', 'TruncMonth', 'TruncQuarter', 'TruncSecond',
     'TruncMinute', 'TruncMonth', 'TruncQuarter', 'TruncSecond', 'TruncTime',
     'TruncWeek', 'TruncYear',
     # math
diff --git a/django/db/models/functions/datetime.py b/django/db/models/functions/datetime.py
index 1876aa7d5c..4d24d2a694 100644
--- a/django/db/models/functions/datetime.py
+++ b/django/db/models/functions/datetime.py
@@ -80,6 +80,11 @@ class ExtractYear(Extract):
     lookup_name = 'year'
 
 
+class ExtractIsoYear(Extract):
+    """Return the ISO-8601 week-numbering year."""
+    lookup_name = 'iso_year'
+
+
 class ExtractMonth(Extract):
     lookup_name = 'month'
 
@@ -126,6 +131,7 @@ DateField.register_lookup(ExtractMonth)
 DateField.register_lookup(ExtractDay)
 DateField.register_lookup(ExtractWeekDay)
 DateField.register_lookup(ExtractWeek)
+DateField.register_lookup(ExtractIsoYear)
 DateField.register_lookup(ExtractQuarter)
 
 TimeField.register_lookup(ExtractHour)
@@ -142,6 +148,12 @@ ExtractYear.register_lookup(YearGte)
 ExtractYear.register_lookup(YearLt)
 ExtractYear.register_lookup(YearLte)
 
+ExtractIsoYear.register_lookup(YearExact)
+ExtractIsoYear.register_lookup(YearGt)
+ExtractIsoYear.register_lookup(YearGte)
+ExtractIsoYear.register_lookup(YearLt)
+ExtractIsoYear.register_lookup(YearLte)
+
 
 class Now(Func):
     template = 'CURRENT_TIMESTAMP'