regex - Oracle regex - does not start with and does not end with

Question

The following Oracle regular expressions do not work and I don't know why.

"Does not start with 'abc'":

^[^(abc)]

"Does not end with 'abc'":

[^(abc)]$

The problem is that the Oracle regex engine does not seem to recognize the 'abc' string as a unit, but only is looking at the letters individually. The parentheses () are supposed to create a string unit. So I don't know what is going on. I used the square brackets only because I believe the 'not' operator ^ only operates inside the brackets, otherwise the ^ is recognized as start of line.

For reference: http://docs.oracle.com/cd/B12037_01/appdev.101/b10795/adfns_re.htm

Answer 1

像这样测试不匹配可能会变得复杂，所以我建议测试匹配并否定结果。

不以abc：

WHERE NOT REGEXP_LIKE(myString, '^abc')

不以abc:

WHERE NOT REGEXP_LIKE(myString, 'abc$')

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至于为什么它不起作用，正如@DavidKnipe 在他的回答中所说：这是因为您正在使用字符类。正则表达式^[^(abc)]解析如下：

• 第一个^说“锚定到字符串的开头”
• The[^(abc)]是一个字符类，它表示“匹配任何单个字符，只要它不是(or aor bor or cor )”。

Answer 2

^否定运算符仅适用于字符类。但是你不应该使用字符类。我不知道 Oracle 正则表达式是否允许环视操作（前瞻和后瞻）。如果他们这样做，请使用^(?!abc)and (?<!abc)$。