数据仓库中有的字段不合格，有特殊字符，比如换行符。

regexp_replace(string INITIAL_STRING, string PATTERN, string REPLACEMENT) Returns the string resulting from replacing all substrings in INITIAL_STRING that match the java regular expression syntax defined in PATTERN with instances of REPLACEMENT. For example, regexp_replace(“foobar”, “oo|ar”, “”) returns ‘fb.’ Note that some care is necessary in using predefined character classes: using ‘\s’ as the second argument will match the letter s; ‘\s’ is necessary to match whitespace, etc.

官网说用两个反斜杠代替一个，即一个反斜杠用来转义。

实践了一下，不行，得4个

转载自：https://www.cnblogs.com/woshimrf/p/hive-string-regexp-replace-usage.html