Refs #28670 -- Moved LIMIT/OFFSET SQL to DatabaseOperations.limit_offset_sql().

Thanks Tim Graham for the review.

django/db/backends/base/operations.py

@@ -204,6 +204,22 @@ class BaseDatabaseOperations:
             ' SKIP LOCKED' if skip_locked else '',
         )
 
+    def _get_limit_offset_params(self, low_mark, high_mark):
+        offset = low_mark or 0
+        if high_mark is not None:
+            return (high_mark - offset), offset
+        elif offset:
+            return self.connection.ops.no_limit_value(), offset
+        return None, offset
+
+    def limit_offset_sql(self, low_mark, high_mark):
+        """Return LIMIT/OFFSET SQL clause."""
+        limit, offset = self._get_limit_offset_params(low_mark, high_mark)
+        return '%s%s' % (
+            (' LIMIT %d' % limit) if limit else '',
+            (' OFFSET %d' % offset) if offset else '',
+        )
+
     def last_executed_query(self, cursor, sql, params):
         """
         Return a string of the query last executed by the given cursor, with

django/db/backends/oracle/operations.py

@@ -233,6 +233,9 @@ END;
         else:
             return "%s"
 
+    def limit_offset_sql(self, low_mark, high_mark):
+        return ''
+
     def last_executed_query(self, cursor, sql, params):
         # https://cx-oracle.readthedocs.io/en/latest/cursor.html#Cursor.statement
         # The DB API definition does not define this attribute.

django/db/models/sql/compiler.py

@@ -532,14 +532,9 @@ class SQLCompiler:
                 result.append('ORDER BY %s' % ', '.join(ordering))
 
             if with_limits:
-                if self.query.high_mark is not None:
-                    result.append('LIMIT %d' % (self.query.high_mark - self.query.low_mark))
-                if self.query.low_mark:
-                    if self.query.high_mark is None:
-                        val = self.connection.ops.no_limit_value()
-                        if val:
-                            result.append('LIMIT %d' % val)
-                    result.append('OFFSET %d' % self.query.low_mark)
+                limit_offset_sql = self.connection.ops.limit_offset_sql(self.query.low_mark, self.query.high_mark)
+                if limit_offset_sql:
+                    result.append(limit_offset_sql)
 
             if for_update_part and not self.connection.features.for_update_after_from:
                 result.append(for_update_part)