尝试以下查询：
select company_code ,
SUM(case when product_code = 10 then 1 else 0 end) as product_10 ,
SUM(case when product_code = 20 then 1 else 0 end) as product_20
from product
group by company_code
用这个
SELECT COUNT( DISTINCT product_code) FROM Product where product_code = 10;
SELECT COUNT( DISTINCT product_code) FROM Product where product_code = 20;
使用子查询的轻微变化（因为我喜欢它们；）：
SELECT S.company_code, S.product_code,
SUM(IF(S.product_code = 10, S.C, 0)) AS `product_10`,
SUM(IF(S.product_code = 20, S.C, 0)) AS `product_20`
FROM (SELECT company_code, product_code, COUNT(*) AS C
FROM Product
GROUP BY company_code, product_code) AS S
GROUP BY S.company_code;
（顺便说一句，人们可能希望使用计数COUNT()可以更好地利用（company_code，product_code）上的潜在索引。不确定，认为......）
生产...
+--------------+--------------+------------+------------+
| company_code | product_code | product_10 | product_20 |
+--------------+--------------+------------+------------+
| 100 | 10 | 3 | 2 |
| 200 | 10 | 1 | 0 |
| 300 | 20 | 0 | 2 |
+--------------+--------------+------------+------------+
3 rows in set (0.00 sec)
...来自该数据集：
mysql> select * from Product;
+--------------+--------------+--------------+
| company_code | product_code | product_name |
+--------------+--------------+--------------+
| 100 | 10 | bag |
| 100 | 10 | bag_2 |
| 100 | 10 | bag_3 |
| 100 | 20 | pencil |
| 100 | 20 | pencil_1 |
| 200 | 10 | bag |
| 300 | 20 | pencil |
| 300 | 20 | pencil_1 |
+--------------+--------------+--------------+
8 rows in set (0.00 sec)
如果您希望这些列是动态的（交叉表/数据透视表），您可以执行以下操作：
SET @sql = NULL;
SELECT
GROUP_CONCAT(DISTINCT
CONCAT(
'SUM(case when product_code = ', product_code,
' then 1 else 0 end) as product_', product_code
)) INTO @sql
FROM product;
SET @sql =
CONCAT('SELECT company_code, ',
@sql,
' FROM product',
' GROUP BY company_code');
PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
第一条语句创建@sql，SUM(xxx然后执行新形成的sql语句。您拥有多少产品并不重要。但请记住，如果您有很多产品，这种展示方式并不直观。