Add details regarding RegEx pattern syntax
diff --git a/_docs/en/sql-reference/sql-functions/040-string-manipulation.md b/_docs/en/sql-reference/sql-functions/040-string-manipulation.md
index 0b4aa6b..e5d7640 100644
--- a/_docs/en/sql-reference/sql-functions/040-string-manipulation.md
+++ b/_docs/en/sql-reference/sql-functions/040-string-manipulation.md
@@ -338,13 +338,20 @@
Matches a regexp pattern to a target string. Returns a boolean value: true if the value matches the regexp, false if the value does not match the regexp.
+
### REGEXP_MATCHES Syntax
REGEXP_MATCHES(string_expression, pattern)
*string_expression* is the string to be matched.
-*pattern* is the regular expression.
+*pattern* is the [Java regular expression pattern](https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/util/regex/Pattern.html).
+
+{% include startnote.html %}
+The regular expression . matches any character except a line terminator unless the [DOTALL flag](https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/util/regex/Pattern.html#DOTALL) is specified.
+By default, the regular expressions ^ and $ ignore line terminators and only match at the beginning and the end, respectively, of the entire input sequence. If [MULTILINE mode](https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/util/regex/Pattern.html#MULTILINE) is activated then ^ matches at the beginning of input and after any line terminator except at the end of input. When in [MULTILINE mode](https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/util/regex/Pattern.html#MULTILINE) $ matches just before a line terminator or the end of the input sequence.
+{% include endnote.html %}
+
### REGEXP_MATCHES Examples
@@ -373,6 +380,30 @@
|--------|
| true |
|--------|
+
+Shows how to turn on different pattern flags to enable case-insensitive matching, to permit whitespace and comments in pattern, etc. Complete list of flags you can find in [Java Doc](https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/util/regex/Pattern.html#field.summary)):
+
+ select regexp_matches('String with newline character
+ ', '(?s).*');
+ +--------+
+ | EXPR$0 |
+ +--------+
+ | true |
+ +--------+
+
+ select regexp_matches('ABC', '(?i)abc');
+ +--------+
+ | EXPR$0 |
+ +--------+
+ | true |
+ +--------+
+
+ select regexp_matches('abc', '(?x)a b c');
+ +--------+
+ | EXPR$0 |
+ +--------+
+ | true |
+ +--------+
