Fixed #19716 -- Added support for microseconds with MySQL 5.6.4 and up

Thanks erik@cederstrand.dk for the report and Tim Graham for the review.

django/db/backends/mysql/base.py

@@ -79,7 +79,7 @@ def adapt_datetime_with_timezone_support(value, conv):
             default_timezone = timezone.get_default_timezone()
             value = timezone.make_aware(value, default_timezone)
         value = value.astimezone(timezone.utc).replace(tzinfo=None)
-    return Thing2Literal(value.strftime("%Y-%m-%d %H:%M:%S"), conv)
+    return Thing2Literal(value.strftime("%Y-%m-%d %H:%M:%S.%f"), conv)
 
 # MySQLdb-1.2.1 returns TIME columns as timedelta -- they are more like
 # timedelta in terms of actual behavior as they are signed and include days --
@@ -175,7 +175,6 @@ class DatabaseFeatures(BaseDatabaseFeatures):
     supports_forward_references = False
     # XXX MySQL DB-API drivers currently fail on binary data on Python 3.
     supports_binary_field = six.PY2
-    supports_microsecond_precision = False
     supports_regex_backreferencing = False
     supports_date_lookup_using_string = False
     can_introspect_binary_field = False
@@ -210,6 +209,10 @@ class DatabaseFeatures(BaseDatabaseFeatures):
         "Confirm support for introspected foreign keys"
         return self._mysql_storage_engine != 'MyISAM'
 
+    @cached_property
+    def supports_microsecond_precision(self):
+        return self.connection.mysql_version >= (5, 6, 4)
+
     @cached_property
     def has_zoneinfo_database(self):
         # MySQL accepts full time zones names (eg. Africa/Nairobi) but rejects