MySQL-NULL安全NOT等于运算符
问题描述：
我很好奇.我知道NULL安全等于运算符< =>，但是是否存在一些NULL安全NOT等于运算符，或者我必须始终使用类似的东西:
I am just curious. I know about NULL safe equal operator <=>, but is there some NULL safe NOT equal operator, or I have to always use something like that:
(tab.id != 1 OR tab.id IS NULL)
或者有人喜欢
!(tab.id <=> 1)
答
COALESCE(tab.id, 0) != 1
如果愿意，可以在这里使用.我遍历参数，并返回不是NULL的第一个值.在这种情况下，如果它是NULL，它将比较0 != 1.尽管它可能会使用更多的符号，但在这种情况下，它仍然更易于管理，而不是被迫总是使用相反的布尔值"作为解决方案.
Can be used here if you like it. I goes through the parameters, and returns the first value that isn't NULL. In this case if it's NULL, it will compare 0 != 1. Although it may use more signs, it's still easier to manage instead of being forced to always have opposite "booleans" as a solution in those cases.
阅读 COALESCE()