Question

我有以下表格：

表：产品

--------------------------       
id_product |  name_product                               
--------------------------      
1          | p1                            
2          | p2                
3          | p3

表：数字

-----------------------
 imei      | id_product  
-----------------------
 56789     | 1   
 56799     | 2
 56713     | 3

表：操作

----------------------
imei     |  date
------------------
56789    |31-07-2017

最后我想得到这个结果：

---------------------------------------
 name_product | number_operation  
---------------------------------------
 p1           | 1   
 p2           | 0
 p3           | 0

谢谢你

Answer 1

这将按产品计算操作次数：

select name_product, sum(num_op)
from product p1
left join number n2
  on n2.id_product = p1.id_product
left join
    (
    select imei, count(operation) as num_op
    from Operation
    group by imei
    ) x
  on x.imei = n2.imei
group by name_product

对于已经进行过操作的产品数量：

select name_product, count(distinct o3.imei)
from product p1
left join number n2
  on n2.id_product = p1.id_product
left join Operation o3
  on o3.imei = n2.imei
group by name_product

Answer 2

可能的解决方案：

SELECT name_product, COUNT(*)
FROM product p
LEFT JOIN number n ON n.id_product = p.id_product
LEFT JOIN operation o ON o.imei = n.imei
GROUP BY p.id_product

Answer 3

SELECT product.id_product,COUNT(number.id_product)
FROM product
INNER JOIN number ON product.id_product = number.id_product;
GROUP BY product.id_product

Answer 4

SELECT   name_product, count (imei) c
FROM   (SELECT   name_product, o.imei
          FROM      (SELECT   p.name_product, n.imei
                       FROM   product p, "number" n
                      WHERE   p.id_product = n.id_product) t
                 LEFT JOIN
                    Operatio o
                 ON t.imei = o.imei)
GROUP BY   name_product

试试此代码

SQL连接查询选择

4 个答案: