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  • sqlalchemy模块

    多表联合查询

    #按用户名摸糊查询
    trans_details.query.join(Uses).filter(Users.username.like('%xx%'))
    #select xxx from trans_details inner join trans_details on users.id=trans_details.user_id where users.username like '%xx%'
    
    #左外联接(left join)
    trans_details.query.outerjoin(Uses).filter(Users.username.like('%xx%'))
    #select xxx from trans_details left outer join trans_details on users.id=trans_details.user_id where users.username like '%xx%'
    
    #以上是已经设置好外键,它自动找到关联的字段.也可以自己指定:
    trans_details.query.join(Uses,trans_details.user_id==Users.id).filter(Users.username.like('%xx%'))
    #select xxx from trans_details inner join trans_details on users.id=trans_details.user_id where users.username like '%xx%'
    
    #另外一个更复杂的例子:
    q=db.session.query(Credit_bills_details.no,Credit_bills_details.amount,Cards.no).outerjoin(Card_trans_details,
    Credit_bills_details.no==Card_trans_details.trans_no).join(Cards,Card_trans_details.to_card_id==Cards.id)
    .filter(Credit_bills_details.credit_bill_id==3)
    
    
    #SELECT credit_bills_details.no AS credit_bills_details_no, credit_bills_details.amount AS credit_bills_details_amount, cards.no AS cards_no
    # FROM credit_bills_details LEFT OUTER JOIN card_trans_details ON credit_bills_details.no = card_trans_details.trans_no INNER JOIN cards
    # ON card_trans_details.to_card_id = cards.id  WHERE credit_bills_details.credit_bill_id = %s
    

      

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  • 原文地址:https://www.cnblogs.com/jabbok/p/14296993.html
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