engine: remove use of cross join (#38691)

It prevented reporting of NULL values.

bijoe/engine.py

@@ -371,7 +371,6 @@ class EngineCube(object):
             where = []
             group_by = []
             order_by = []
-            join_conditions = []
 
             for dimension_name, values in filters:
                 dimension = self.dimensions[dimension_name]
@@ -381,7 +380,7 @@ class EngineCube(object):
                 if dimension.filter_needs_join and dimension.join:
                     joins.update(dimension.join)
                 if dimension.filter_in_join:
-                    join_conditions.append(condition)
+                    assert False, 'filter in join is not supported anymore'
                 else:
                     where.append(condition)
 
@@ -403,8 +402,7 @@ class EngineCube(object):
             sql = 'SELECT ' + ', '.join(projections)
             table_expression = ' %s' % self.cube.fact_table
             if joins:
-                table_expression = self.build_table_expression(
-                    joins, self.fact_table, other_conditions=join_conditions)
+                table_expression = self.build_table_expression(joins, self.fact_table)
             sql += ' FROM %s' % table_expression
             where_conditions = 'true'
             if where:
@@ -450,7 +448,14 @@ class EngineCube(object):
                     ))
                 yield cells
 
-    def build_table_expression(self, joins, table_name, other_conditions=None):
+    JOIN_KINDS = {
+        'inner': 'INNER JOIN',
+        'left': 'LEFT OUTER JOIN',
+        'right': 'RIGHT OUTER JOIN',
+        'full': 'FULL OUTER JOIN',
+    }
+
+    def build_table_expression(self, joins, table_name):
         '''Recursively build the table expression from the join tree,
            starting from the fact table'''
 
@@ -461,45 +466,37 @@ class EngineCube(object):
             master_table = join.master_table or self.fact_table
             join_tree.setdefault(master_table, {}).setdefault(join.kind, {})[join.name] = join
 
-        def build_table_expression_helper(join_tree, table_name, alias=None, top=True, other_conditions=None):
+        def build_table_expression_helper(join_tree, table_name, alias=None, top=True):
+            contain_joins = False
+
             sql = table_name
             if alias:
                 sql += ' AS %s' % quote(alias)
-            add_paren = False
+
             for kind in ['left', 'inner', 'right', 'full']:
                 joins = join_tree.get(alias or table_name, {}).get(kind)
                 if not joins:
                     continue
-                add_paren = True
-                join_kinds = {
-                    'inner': 'INNER JOIN',
-                    'left': 'LEFT OUTER JOIN',
-                    'right': 'RIGHT OUTER JOIN',
-                    'full': 'FULL OUTER JOIN',
-                }
-                sql += ' %s ' % join_kinds[kind]
-                sub_joins = []
-                conditions = []
-                if other_conditions:
-                    conditions = other_conditions
-                    other_conditions = None
                 for join_name, join in joins.iteritems():
-                    sub_joins.append(
-                        build_table_expression_helper(join_tree, join.table, alias=join.name, top=False))
-                    conditions.append('%s.%s = %s.%s' % (
+                    contain_joins = True
+                    sql += ' %s ' % self.JOIN_KINDS[kind]
+                    sql += ' ' + build_table_expression_helper(join_tree, join.table, alias=join.name, top=False)
+                    condition = '%s.%s = %s.%s' % (
                         alias or table_name,
                         join.master.split('.')[-1],
-                        quote(join.name), join.detail))
-                sub_join = ' CROSS JOIN '.join(sub_joins)
-                if len(sub_joins) > 1:
-                    sub_join = '(%s)' % sub_join
-                sql += sub_join
-                sql += ' ON %s' % ' AND '.join(conditions)
-            if not top and add_paren:
+                        quote(join.name),
+                        join.detail)
+                    sql += ' ON ' + condition
+
+            # if the table expression contains joins and is not the full table
+            # expression but used in another join, it must be quoted with
+            # parenthesis
+            if not top and contain_joins:
                 sql = '(%s)' % sql
+
             return sql
-        return build_table_expression_helper(
-            join_tree, table_name, other_conditions=other_conditions)
+
+        return build_table_expression_helper(join_tree, table_name)
 
 
 class Engine(object):

bijoe/schemas.py

@@ -328,7 +328,7 @@ class Join(Base):
         'kind': join_kind,
     }
 
-    kind = 'right'
+    kind = 'full'
 
     @property
     def master_table(self):