mysql - SQL 显示从不更改但根据需要更新其他列的列的静态值

Question

我想知道在 sql 中拥有一个由于 WHERE 子句而不会显示的静态列的最佳方法是什么。在下面的代码中我有一个设计师。我希望所有设计师都能出现，即使他们不满足 WHERE 条件，但具有与 WHERE 条件相关的值。

SELECT first_assigned_to AS Designer, 
           Count(DISTINCT quote_email) AS totalLeads 
    FROM   quotes_new_assigned 
    WHERE  date_first_assigned_to >= YEAR(CURDATE())
    GROUP  BY designer 

This is what the SELECT will give us at the end of the year

adam   38
bob    1711
brenda 823
chris  7
dave   426
diane  52

This is what I would like it to give (values dont matter, just notice how the ones that do not have any quotes assigned to them still show up)

adam   0
bob    0
brenda 3
chris  1
dave   0
diane  4

Answer 1

您可以在 COUNT 内使用 CASE WHEN 来做到这一点。

SELECT first_assigned_to AS Designer, 
Count(DISTINCT CASE WHEN date_first_assigned_to >= YEAR(CURDATE()) THEN quote_email END) AS totalLeads 
FROM  quotes_new_assigned  
GROUP BY first_assigned_to;