Oracle不等于运算符 [英] Oracle Not Equals Operator

问题描述

有两个不等于运算符-!=和<>.

There are two not equals operator - != and <>.

它们之间有什么区别?我听说!=比其他字符串更有效.任何人都可以对此声明做出定性评论.

What's the difference between them? I heard that != is more efficient than other for comparing strings. Could anyone give a qualitative comment on this statement.

推荐答案

它们是相同的(第三种形式是^=).

They are the same (as is the third form, ^=).

但是请注意，从解析器的角度来看，它们仍然被认为是不同的，即为!=定义的存储轮廓将与<>或^=不匹配.

Note, though, that they are still considered different from the point of view of the parser, that is a stored outline defined for a != won't match <> or ^=.

这与PostgreSQL不同，在解析器处于解析阶段时，解析器将!=和<>对待，因此您不能重载!=和<>作为不同的运算符.

This is unlike PostgreSQL where the parser treats != and <> yet on parsing stage, so you cannot overload != and <> to be different operators.

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