Fixed #28926 -- Fixed loss of precision of big DurationField values on SQLite and MySQL.

2 files changed, 4 insertions, 2 deletions

diff --git a/django/db/backends/mysql/operations.py b/django/db/backends/mysql/operations.py
index 7c901d78d8..ad4c13652e 100644
--- a/django/db/backends/mysql/operations.py
+++ b/django/db/backends/mysql/operations.py
@@ -3,6 +3,7 @@ import uuid
 from django.conf import settings
 from django.db.backends.base.operations import BaseDatabaseOperations
 from django.utils import timezone
+from django.utils.duration import duration_microseconds
 from django.utils.encoding import force_text
 
 
@@ -105,7 +106,7 @@ class DatabaseOperations(BaseDatabaseOperations):
             return "TIME(%s)" % (field_name)
 
     def date_interval_sql(self, timedelta):
-        return "INTERVAL '%06f' SECOND_MICROSECOND" % timedelta.total_seconds()
+        return 'INTERVAL %s MICROSECOND' % duration_microseconds(timedelta)
 
     def format_for_duration_arithmetic(self, sql):
         return 'INTERVAL %s MICROSECOND' % sql
diff --git a/django/db/backends/sqlite3/base.py b/django/db/backends/sqlite3/base.py
index d15352dcc6..d3caa6d12a 100644
--- a/django/db/backends/sqlite3/base.py
+++ b/django/db/backends/sqlite3/base.py
@@ -17,6 +17,7 @@ from django.utils import timezone
 from django.utils.dateparse import (
     parse_date, parse_datetime, parse_duration, parse_time,
 )
+from django.utils.duration import duration_microseconds
 
 from .client import DatabaseClient                          # isort:skip
 from .creation import DatabaseCreation                      # isort:skip
@@ -471,7 +472,7 @@ def _sqlite_time_diff(lhs, rhs):
 def _sqlite_timestamp_diff(lhs, rhs):
     left = backend_utils.typecast_timestamp(lhs)
     right = backend_utils.typecast_timestamp(rhs)
-    return (left - right).total_seconds() * 1000000
+    return duration_microseconds(left - right)
 
 
 def _sqlite_regexp(re_pattern, re_string):