我有一个名为_gender的变量，即为0-1或2
0 male
1 female
2 everyone
我想实现变量为所有人的情况，然后我希望性别为0或1
但是如果它是0或1，那么我应该与仅作为变量的用户匹配
SELECT * FROM TABLE
WHERE COUNTRY = 1
AND Gender = "IF _gender == 2, then i need to get gender either = 0 or 1, else i get the value of the variable (to match 0 or 1)"
我认为您正在寻找类似的东西：
Often
nullis used for the value to mean everyone. In that case, you need to phrase it as: