oracle regular expression Pattern Description in 11g

Pattern Description

Anchoring Characters	Character Class Desc ^ Anchor the expression to the start of a line $ Anchor the expression to the end of a line
Equivalence Classes	Character Class Desc = = Oracle supports the equivalence classes through the POSIX '[==]' syntax. A base letter and all of its accented versions constitute an equivalence class. For example, the equivalence class '[=a=]' matches ä and â. The equivalence classes are valid only inside the bracketed expression
Match Options	Character Class Desc c Case sensitive matching i Case insensitive matching m Treat source string as multi-line activating Anchor chars n Allow the period (.) to match any newline character
Posix Characters	Character Class Desc [:alnum:] Alphanumeric characters [:alpha:] Alphabetic characters [:blank:] Blank Space Characters [:cntrl:] Control characters (nonprinting) [:digit:] Numeric digits [:graph:] Any [:punct:], [:upper:], [:lower:], and [:digit:] chars [:lower:] Lowercase alphabetic characters [:print:] Printable characters [:punct:] Punctuation characters [:space:] Space characters (nonprinting), such as carriage return, newline, vertical tab, and form feed [:upper:] Uppercase alphabetic characters [:xdigit:] Hexidecimal characters
Quantifier Characters	Character Class Desc * Match 0 or more times ? Match 0 or 1 time + Match 1 or more times {m} Match exactly m times {m,} Match at least m times {m, n} Match at least m times but no more than n times \n Cause the previous expression to be repeated n times
Alternative Matching And Grouping Characters	Character Class Desc | Separates alternates, often used with grouping operator () ( ) Groups subexpression into a unit for alternations, for quantifiers, or for backreferencing (see "Backreferences" section) [char] Indicates a character list; most metacharacters inside a character list are understood as literals, with the exception of character classes, and the ^ and - metacharacters

n match parameter:
'c' = case sensitive
'i' = case insensitive search
'm' = treats the source string as multiple lines
'n' = allows the period (.) wild character to match newline
'x' = ignore whitespace characters

1. REGEXP_COUNT

REGEXP_COUNT
Syntax	REGEXP_COUNT(source_string, pattern[[, start_position], [match_parameter]])

2. REGEXP_INSTR

REGEXP_INSTR
Syntax	REGEXP_INSTR(source_string, pattern[[, start_position][, occurrence][, return_option][, match_parameter][, sub_expression]])

3. REGEXP_LIKE

REGEXP_LIKE
Syntax	REGEXP_LIKE(source_string, pattern, match_parameter)

4. REGEXP_REPLACE

REGEXP_REPLACE
Syntax	REGEXP_REPLACE(source_string, pattern, replace_string, position, occurrence, match_parameter)

5. REGEXP_SUBSTR

REGEXP_SUBSTR
Syntax	REGEXP_SUBSTR(source_string, pattern [, position [, occurrence [, match_parameter]]])