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我想将 SQL 查询转换为SQLalcheny。这是我的查询。 

**SELECT
  *
FROM (
  -- Get the first time each user viewed the homepage.
  SELECT
    pr.id, pr.name, pr.sku, ca.name as "Catergory Nmae", su.name as "Supplier Name", br.name as "Brand Name"
  FROM public."products" pr
LEFT JOIN public."categories" ca on pr.category_id = ca.id
LEFT JOIN public."suppliers" su on pr.supplier_id = su.id
LEFT JOIN public."brands" br on pr.brand_id = br.id
    GROUP BY pr.id, ca.name, su.name, br.name
) er LEFT JOIN LATERAL (
  -- For each row, get the first time the user_id did the enter_credit_card
  -- event, if one exists within two weeks of view_homepage_time.
  SELECT
    pp.scraped_price,
pp.process_date,
re.name
    FROM public."product_urls" pu
LEFT JOIN public."productPriceDetails" pp on pp.product_id = pu.product_id and pp.url_id = pu.id and pp.process_date = '2020-04-17'
LEFT JOIN public."retailers" re on pu.retailer_id = re.id
--GROUP BY  er.id, re.name
    LIMIT 5
) e2 ON true**

我创建了两个子查询，即“init_query”和“sub_qry_lateral”，如下所示

init_query = db.session.query(Product.id, Product.name.label('Product_Name'), Product.sku,
                  Category.name.label("Catergory_Name") , Supplier.name.label('Supplier_name'), Brand.name.label('Brand_Name') ) \
                .join( Category,  Product.category_id == Category.id, isouter=True) \
                .join(Supplier, Product.supplier_id == Supplier.id, isouter=True) \
                .join(Brand, Brand.id == Product.brand_id, isouter=True) \
                .group_by(Product.id, Category.name, Supplier.name, Brand.name) \
                .subquery('init_query')

    **sub_qry_lateral** = db.session.query(ProductUrl.product_id, 

ProductPriceDetails.scraped_price,ProductPriceDetails.process_date,Retailer.name ) \
            .join( ProductPriceDetails, and_(ProductPriceDetails.product_id == ProductUrl.product_id , ProductPriceDetails.url_id == ProductUrl.id , ProductPriceDetails.process_date =='2020-04-17'), isouter=True) \
            .join(Retailer,  ProductUrl.retailer_id == Retailer.id,  isouter=True) \
            .limit(5) \
            .subquery('sub_qry_lateral') \
            .lateral()
and combine it as follows

db_result = db.session.query(init_query,  sub_qry_lateral.c.scraped_price, sub_qry_lateral.c.process_date) \
                .join(sub_qry_lateral, init_query.c.id == sub_qry_lateral.c.product_id, isouter=True )

但它没有给出正确的答案。它仅输出子查询“init_query”的结果集

任何帮助表示赞赏

4

1 回答 1

1

最后我可以解决它。我将其重写为

db_result = db.session.query(init_query, sub_qry_lateral.c.scraped_price, sub_qry_lateral.c.process_date).j​​oin(sub_qry_lateral, true())

删除条件并添加 true()

于 2020-04-19T11:44:54.750 回答