Question

我有这个查询

MYSQL：

SELECT COUNT(op.quantity) AS quantity_sold, op.model AS model_number,
op.name AS product_name, ptc.category_id, cd.name 
FROM ((`order_product` op INNER JOIN `product` p ON op.product_id = p.product_id) 
INNER JOIN (`product_to_category` ptc 
INNER JOIN `category_description` cd ON ptc.category_id = cd.category_id) ON op.product_id = ptc.product_id)
INNER JOIN `order` o on o.order_id = op.order_id  GROUP BY op.model ORDER BY quantity_sold DESC;

我尝试使用此代码来计算否。上述结果的行数。

SELECT COUNT(*) AS total FROM ((`order_product` op INNER JOIN `product` p ON op.product_id = p.product_id) 
INNER JOIN (`product_to_category` ptc 
INNER JOIN `category_description` cd ON ptc.category_id = cd.category_id) ON op.product_id = ptc.product_id)
INNER JOIN `order` o on o.order_id = op.order_id  GROUP BY op.model;

但我无法获得计数单值。

为了分页，我需要将第一个查询返回的行数作为单个值。

Answer 1

如果您想要查询返回的行计数，将其包装在外部查询中应该可以提供您想要的内容：

SELECT COUNT(*) AS row_count FROM (

  SELECT 
      COUNT(op.quantity) AS quantity_sold, 
      op.model AS model_number,
      op.name AS product_name, 
      ptc.category_id, 
      cd.name 
  FROM order_product op 
  INNER JOIN product p ON op.product_id = p.product_id
  INNER JOIN product_to_category ptc ON op.product_id = ptc.product_id
  INNER JOIN category_description cd ON ptc.category_id = cd.category_id
  INNER JOIN `order` o on o.order_id = op.order_id  
  GROUP BY op.model
  ORDER BY quantity_sold DESC
) A;

无法计算从查询返回的行数

1 个答案: