创建子查询在子查询中选择使用COUNT进行COUNT个

Question

有这个COUNT子查询，但是我无法使用语法。

    SELECT products.client_id,
       clients.name AS client_name,
       cars.vin,
       cars.make,  
    cars.model
   (SELECT COUNT(*) FROM manheim_auction_listings AS listings_sub
        JOIN products ON 
          manheim_auction_listings.product_id  = products.id 
        JOIN product_purchases ON
           products.current_product_purchase_id = product_purchases.id 
       WHERE listings_sub.car_id = manheim_auction_listings.car_id AND                      
          listings_sub.id <> manheim_auction_listings.id and         
          manheim_auction_listings.product_purchase_id = 
          product_purchases.id) as previous_auction_count 
      FROM manheim_auction_listings
      JOIN cars ON 
      cars.id = manheim_auction_listings.car_id .....

（SELECT COUNT（*）不会与JOIN的I Need一起传递语法以获得正确的计数。

Answer 1

您在内部查询中缺少GROUP BY 。

WHERE listings_sub.car_id = manheim_auction_listings.car_id AND                      
      listings_sub.id <> manheim_auction_listings.id and         
      manheim_auction_listings.product_purchase_id = 
      product_purchases.id
      GROUP BY <list_of_column(s)>

此外，还有另外几个语法错误

你缺少逗号,刚过cars.model列必须被分开, 。

 cars.model
  (SELECT COUNT(*) FROM manheim_auction_listings AS listings_sub