逻辑(二进制)运算符Logical (binary) operators
支持在 bool
类型的两个值之间使用以下逻辑运算符:The following logical operators are supported between two values of the bool
type:
备注
这些逻辑运算符有时称为布尔运算符,有时称为二元运算符。These logical operators are sometimes referred-to as Boolean operators, and sometimes as binary operators. 这些名称都是同义词。The names are all synonyms.
操作员名称Operator name | 语法Syntax | 含义Meaning |
---|---|---|
相等Equality | == |
如果两个操作数均非 null 且彼此相等,则生成 true 。Yields true if both operands are non-null and equal to each other. 否则为 false 。Otherwise, false . |
不相等Inequality | != |
如果两个操作数不相等或至少有一个为 null,则生成 true 。Yields true if either one (or both) of the operands are null, or they are not equal to each other. 否则为 true 。Otherwise, true . |
逻辑与Logical and | and |
如果两个操作数都为 true ,则生成 true 。Yields true if both operands are true . |
逻辑或Logical or | or |
如果其中一个操作数是 true ,则无论其他操作数如何,都将生成 true 。Yields true if one of the operands is true , regardless of the other operand. |
备注
考虑到布尔 null 值 bool(null)
的行为,我们可以说:两个布尔 null 值既不相等也不不相等(换句话说,bool(null) == bool(null)
和 bool(null) != bool(null)
都生成值 false
)。Due to the behavior of the Boolean null value bool(null)
, two Boolean null values are neither equal nor non-equal (in other words, bool(null) == bool(null)
and bool(null) != bool(null)
both yield the value false
).
另一方面,and
/or
将 null 值视为等效于 false
,因此 bool(null) or true
为 true
,bool(null) and true
为 false
。On the other hand, and
/or
treat the null value as equivalent to false
, so bool(null) or true
is true
, and bool(null) and true
is false
.