试图在sql中加入两个选择的结果

Question

我是mysql的新手，无法弄清楚如何加入这两个选择的结果。有什么建议吗？

select COUNT(COLORANTCODE) as Colorant_Count from Formula group by COLORANTCODE;

select COLORANTNAME from Colorant;

我所尝试的一切都没有效果。

Formula包含COLORANTCODE，它是包含COLORANTCODE和COLORANTNAME的Colorant的FK。

我需要结果表包含COLORANTNAME以及它在公式中显示的次数。

Answer 1

利用LEFT JOIN

SELECT c.colorantname, COALESCE(COUNT(f.colorantcode), 0) count
  FROM colorant c LEFT JOIN Formula f
    ON c.colorantcode = f.colorantcode
 GROUP BY c.colorantcode, c.colorantname

推荐阅读：

• A Visual Explanation of SQL Joins

Answer 2

Select COLORANTCODE, Count(*) as Colorant_count  
from Formula  
Group by COLORANTCODE