Syntax

Regular expressions are a notation for describing sets of character strings. When a particular string is in the set described by a regular expression, we often say that the regular expression matches the string. The simplest regular expression is a single literal character. Except for the metacharacters like *+?()|, characters match themselves. To match a metacharacter, escape it with a backslash:

[mainyaa]

BigQueryで使える正規表現