collate.py 文件源码

def get_selects(self):
        """
        Constructs select queries for this aggregation

        Returns: a dictionary of group : queries pairs where
            group are the same keys as groups
            queries is a list of Select queries, one for each date in dates
        """
        queries = {}

        for group, groupby in self.groups.items():
            columns = [groupby]
            columns += self._get_aggregates_sql(group)

            gb_clause = make_sql_clause(groupby, ex.literal_column)
            query = ex.select(columns=columns, from_obj=self.from_obj)\
                      .group_by(gb_clause)

            queries[group] = [query]

        return queries