diff options
Diffstat (limited to 'django/db/models/sql')
| -rw-r--r-- | django/db/models/sql/compiler.py | 28 |
1 files changed, 18 insertions, 10 deletions
diff --git a/django/db/models/sql/compiler.py b/django/db/models/sql/compiler.py index c705d33af8..84e240d1f4 100644 --- a/django/db/models/sql/compiler.py +++ b/django/db/models/sql/compiler.py @@ -399,7 +399,18 @@ class SQLCompiler: raise DatabaseError('LIMIT/OFFSET not allowed in subqueries of compound statements.') if compiler.get_order_by(): raise DatabaseError('ORDER BY not allowed in subqueries of compound statements.') - parts = (compiler.as_sql() for compiler in compilers) + parts = () + for compiler in compilers: + try: + parts += (compiler.as_sql(),) + except EmptyResultSet: + # Omit the empty queryset with UNION and with DIFFERENCE if the + # first queryset is nonempty. + if combinator == 'union' or (combinator == 'difference' and parts): + continue + raise + if not parts: + return [], [] combinator_sql = self.connection.ops.set_operators[combinator] if all and combinator == 'union': combinator_sql += ' ALL' @@ -422,16 +433,7 @@ class SQLCompiler: refcounts_before = self.query.alias_refcount.copy() try: extra_select, order_by, group_by = self.pre_sql_setup() - distinct_fields = self.get_distinct() - - # This must come after 'select', 'ordering', and 'distinct' -- see - # docstring of get_from_clause() for details. - from_, f_params = self.get_from_clause() - for_update_part = None - where, w_params = self.compile(self.where) if self.where is not None else ("", []) - having, h_params = self.compile(self.having) if self.having is not None else ("", []) - combinator = self.query.combinator features = self.connection.features if combinator: @@ -439,6 +441,12 @@ class SQLCompiler: raise NotSupportedError('{} is not supported on this database backend.'.format(combinator)) result, params = self.get_combinator_sql(combinator, self.query.combinator_all) else: + distinct_fields = self.get_distinct() + # This must come after 'select', 'ordering', and 'distinct' + # (see docstring of get_from_clause() for details). + from_, f_params = self.get_from_clause() + where, w_params = self.compile(self.where) if self.where is not None else ("", []) + having, h_params = self.compile(self.having) if self.having is not None else ("", []) result = ['SELECT'] params = [] |