sql to sqlalchemy 转换

select to_char(date_published, 'yyyymm') yo from blog group by yo;

转换成sqlalchemy 语句

 

可以使用 extract()

In[3]: year_field = db.func.extract('year', ArticleModel.date_published)



In[4]: month_field = db.func.extract('month', ArticleModel.date_published)



In[5]: yonth_field = year_field *100+ month_field



In[6]:print db.session.query(yonth_field.label('yonth'), db.func.count(1)).group_by('yonth')



SELECT EXTRACT(year FROM article_meta.date_published)*:param_1 + EXTRACT(month FROM article_meta.date_published)AS yonth, count(:param_2)AS count_1 

FROM article_meta JOIN article ON article_meta.id = article.id GROUPBY yonth

 也可以 可以通过 func 直接调用数据库支持的函数或存储过程

yonth = db.func.to_char(ArticleModel.date_published,'yyyymm').label('yonth')

archive_list =(db.session.query(yonth,                                 

    db.func.count(1)).group_by('yonth').all())

 感谢python 邮件列表中 jjx 提供帮助