如何在MySql中对两列执行布尔逻辑，其中一列是Varchar

Question

这是这个问题的续集。

我想在MySql select中将三列合并为一列。前两列是布尔值，第三列是字符串，有时为null。这导致了奇怪的结果：

Select *, (payment1_paid && ((payment2_paid || payment2_type ="none"))) as paid_in_full from payments 

注意：payment1_paid为布尔值，payment2_paid为布尔值；payment2_type为varchar。

注意：请忽略这个表的结构有多荒谬。在每一段糟糕的代码背后都有一个很长的解释：）

编辑：我对varchar值的Null不感兴趣。我只想知道它是否真的"没有"

提前感谢您的帮助！

Answer 1

如果null不感兴趣，那么对您来说：

Select *, 
      (payment1_paid && ((payment2_paid || (payment_type IS NOT NULL && payment_type="none"))) 
         as paid_in_full 
from payments

祝你好运！

Answer 2

我想您希望NULL为false？尝试(payment_paid IS NULL || payment2_type = "none")

Answer 3

Select *, 
      (payment1_paid && ((payment2_paid || coalesce(payment2_type,"null") ="none"))) 
         as paid_in_full 
from payments