expr NOT REGEXP pat, expr NOT RLIKE pat

This is the same as NOT (expr REGEXP pat).

expr REGEXP pat, expr RLIKE pat

Returns 1 if the string expr matches the regular expression specified by the pattern pat, 0 otherwise. If expr or pat is NULL, the return value is NULL.

REGEXP and RLIKE are synonyms for REGEXP_LIKE().

For additional information about how matching occurs, see the description for REGEXP_LIKE().

mysql> SELECT 'Michael!' REGEXP '.*';
+------------------------+
| 'Michael!' REGEXP '.*' |
+------------------------+
|                      1 |
+------------------------+
mysql> SELECT 'new*\n*line' REGEXP 'new\\*.\\*line';
+---------------------------------------+
| 'new*\n*line' REGEXP 'new\\*.\\*line' |
+---------------------------------------+
|                                     0 |
+---------------------------------------+
mysql> SELECT 'a' REGEXP '^[a-d]';
+---------------------+
| 'a' REGEXP '^[a-d]' |
+---------------------+
|                   1 |
+---------------------+

REGEXP_INSTR(expr, pat[, pos[, occurrence[, return_option[, match_type]]]])

Returns the starting index of the substring of the string expr that matches the regular expression specified by the pattern pat, 0 if there is no match. If expr or pat is NULL, the return value is NULL. Character indexes begin at 1.

REGEXP_INSTR() takes these optional arguments:

For additional information about how matching occurs, see the description for REGEXP_LIKE().

mysql> SELECT REGEXP_INSTR('dog cat dog', 'dog');
+------------------------------------+
| REGEXP_INSTR('dog cat dog', 'dog') |
+------------------------------------+
|                                  1 |
+------------------------------------+
mysql> SELECT REGEXP_INSTR('dog cat dog', 'dog', 2);
+---------------------------------------+
| REGEXP_INSTR('dog cat dog', 'dog', 2) |
+---------------------------------------+
|                                     9 |
+---------------------------------------+
mysql> SELECT REGEXP_INSTR('aa aaa aaaa', 'a{2}');
+-------------------------------------+
| REGEXP_INSTR('aa aaa aaaa', 'a{2}') |
+-------------------------------------+
|                                   1 |
+-------------------------------------+
mysql> SELECT REGEXP_INSTR('aa aaa aaaa', 'a{4}');
+-------------------------------------+
| REGEXP_INSTR('aa aaa aaaa', 'a{4}') |
+-------------------------------------+
|                                   8 |
+-------------------------------------+

REGEXP_LIKE(expr, pat[, match_type])

Returns 1 if the string expr matches the regular expression specified by the pattern pat, 0 otherwise. If expr or pat is NULL, the return value is NULL.

The pattern can be an extended regular expression, the syntax for which is discussed in Regular Expression Syntax. The pattern need not be a literal string. For example, it can be specified as a string expression or table column.

The optional match_type argument is a string that may contain any or all the following characters specifying how to perform matching:

If characters specifying contradictory options are specified within match_type, the rightmost one takes precedence.

By default, regular expression operations use the character set and collation of the expr and pat arguments when deciding the type of a character and performing the comparison. If the arguments have different character sets or collations, coercibility rules apply as described in Section 12.8.4, “Collation Coercibility in Expressions”. Arguments may be specified with explicit collation indicators to change comparison behavior.

mysql> SELECT REGEXP_LIKE('CamelCase', 'CAMELCASE');
+---------------------------------------+
| REGEXP_LIKE('CamelCase', 'CAMELCASE') |
+---------------------------------------+
|                                     1 |
+---------------------------------------+
mysql> SELECT REGEXP_LIKE('CamelCase', 'CAMELCASE' COLLATE utf8mb4_0900_as_cs);
+------------------------------------------------------------------+
| REGEXP_LIKE('CamelCase', 'CAMELCASE' COLLATE utf8mb4_0900_as_cs) |
+------------------------------------------------------------------+
|                                                                0 |
+------------------------------------------------------------------+

match_type may be specified with the c or i characters to override the default case sensitivity. Exception: If either argument is a binary string, the arguments are handled in case-sensitive fashion as binary strings, even if match_type contains the i character.

mysql> SELECT REGEXP_LIKE('Michael!', '.*');
+-------------------------------+
| REGEXP_LIKE('Michael!', '.*') |
+-------------------------------+
|                             1 |
+-------------------------------+
mysql> SELECT REGEXP_LIKE('new*\n*line', 'new\\*.\\*line');
+----------------------------------------------+
| REGEXP_LIKE('new*\n*line', 'new\\*.\\*line') |
+----------------------------------------------+
|                                            0 |
+----------------------------------------------+
mysql> SELECT REGEXP_LIKE('a', '^[a-d]');
+----------------------------+
| REGEXP_LIKE('a', '^[a-d]') |
+----------------------------+
|                          1 |
+----------------------------+

mysql> SELECT REGEXP_LIKE('abc', 'ABC');
+---------------------------+
| REGEXP_LIKE('abc', 'ABC') |
+---------------------------+
|                         1 |
+---------------------------+
mysql> SELECT REGEXP_LIKE('abc', 'ABC', 'c');
+--------------------------------+
| REGEXP_LIKE('abc', 'ABC', 'c') |
+--------------------------------+
|                              0 |
+--------------------------------+

REGEXP_REPLACE(expr, pat, repl[, pos[, occurrence[, match_type]]])

Replaces occurrences in the string expr that match the regular expression specified by the pattern pat with the replacement string repl, and returns the resulting string. If expr, pat, or repl is NULL, the return value is NULL.

REGEXP_REPLACE() takes these optional arguments:

The result returned by this function uses the character set and collation of the expression searched for matches.

For additional information about how matching occurs, see the description for REGEXP_LIKE().

mysql> SELECT REGEXP_REPLACE('a b c', 'b', 'X');
+-----------------------------------+
| REGEXP_REPLACE('a b c', 'b', 'X') |
+-----------------------------------+
| a X c                             |
+-----------------------------------+
mysql> SELECT REGEXP_REPLACE('abc def ghi', '[a-z]+', 'X', 1, 3);
+----------------------------------------------------+
| REGEXP_REPLACE('abc def ghi', '[a-z]+', 'X', 1, 3) |
+----------------------------------------------------+
| abc def X                                          |
+----------------------------------------------------+

REGEXP_SUBSTR(expr, pat[, pos[, occurrence[, match_type]]])

Returns the substring of the string expr that matches the regular expression specified by the pattern pat, NULL if there is no match. If expr or pat is NULL, the return value is NULL.

REGEXP_SUBSTR() takes these optional arguments:

The result returned by this function uses the character set and collation of the expression searched for matches.

For additional information about how matching occurs, see the description for REGEXP_LIKE().

mysql> SELECT REGEXP_SUBSTR('abc def ghi', '[a-z]+');
+----------------------------------------+
| REGEXP_SUBSTR('abc def ghi', '[a-z]+') |
+----------------------------------------+
| abc                                    |
+----------------------------------------+
mysql> SELECT REGEXP_SUBSTR('abc def ghi', '[a-z]+', 1, 3);
+----------------------------------------------+
| REGEXP_SUBSTR('abc def ghi', '[a-z]+', 1, 3) |
+----------------------------------------------+
| ghi                                          |
+----------------------------------------------+

^

Match the beginning of a string.

mysql> SELECT REGEXP_LIKE('fo\nfo', '^fo$');                   -> 0
mysql> SELECT REGEXP_LIKE('fofo', '^fo');                      -> 1

$

Match the end of a string.

mysql> SELECT REGEXP_LIKE('fo\no', '^fo\no$');                 -> 1
mysql> SELECT REGEXP_LIKE('fo\no', '^fo$');                    -> 0

.

Match any character (including carriage return and newline, although to match these in the middle of a string, the m (multiple line) match-control character or the (?m) within-pattern modifier must be given).

mysql> SELECT REGEXP_LIKE('fofo', '^f.*$');                    -> 1
mysql> SELECT REGEXP_LIKE('fo\r\nfo', '^f.*$');                -> 0
mysql> SELECT REGEXP_LIKE('fo\r\nfo', '^f.*$', 'm');           -> 1
mysql> SELECT REGEXP_LIKE('fo\r\nfo', '(?m)^f.*$');           -> 1

a*

Match any sequence of zero or more a characters.

mysql> SELECT REGEXP_LIKE('Ban', '^Ba*n');                     -> 1
mysql> SELECT REGEXP_LIKE('Baaan', '^Ba*n');                   -> 1
mysql> SELECT REGEXP_LIKE('Bn', '^Ba*n');                      -> 1

a+

Match any sequence of one or more a characters.

mysql> SELECT REGEXP_LIKE('Ban', '^Ba+n');                     -> 1
mysql> SELECT REGEXP_LIKE('Bn', '^Ba+n');                      -> 0

a?

Match either zero or one a character.

mysql> SELECT REGEXP_LIKE('Bn', '^Ba?n');                      -> 1
mysql> SELECT REGEXP_LIKE('Ban', '^Ba?n');                     -> 1
mysql> SELECT REGEXP_LIKE('Baan', '^Ba?n');                    -> 0

de|abc

Alternation; match either of the sequences de or abc.

mysql> SELECT REGEXP_LIKE('pi', 'pi|apa');                     -> 1
mysql> SELECT REGEXP_LIKE('axe', 'pi|apa');                    -> 0
mysql> SELECT REGEXP_LIKE('apa', 'pi|apa');                    -> 1
mysql> SELECT REGEXP_LIKE('apa', '^(pi|apa)$');                -> 1
mysql> SELECT REGEXP_LIKE('pi', '^(pi|apa)$');                 -> 1
mysql> SELECT REGEXP_LIKE('pix', '^(pi|apa)$');                -> 0

(abc)*

Match zero or more instances of the sequence abc.

mysql> SELECT REGEXP_LIKE('pi', '^(pi)*$');                    -> 1
mysql> SELECT REGEXP_LIKE('pip', '^(pi)*$');                   -> 0
mysql> SELECT REGEXP_LIKE('pipi', '^(pi)*$');                  -> 1

{1}, {2,3}

Repetition; {n} and {m,n} notation provide a more general way of writing regular expressions that match many occurrences of the previous atom (or “piece”) of the pattern. m and n are integers.

To be more precise, a{n} matches exactly n instances of a. a{n,} matches n or more instances of a. a{m,n} matches m through n instances of a, inclusive. If both m and n are given, m must be less than or equal to n.

mysql> SELECT REGEXP_LIKE('abcde', 'a[bcd]{2}e');              -> 0
mysql> SELECT REGEXP_LIKE('abcde', 'a[bcd]{3}e');              -> 1
mysql> SELECT REGEXP_LIKE('abcde', 'a[bcd]{1,10}e');           -> 1

[a-dX], [^a-dX]

Matches any character that is (or is not, if ^ is used) either a, b, c, d or X. A - character between two other characters forms a range that matches all characters from the first character to the second. For example, [0-9] matches any decimal digit. To include a literal ] character, it must immediately follow the opening bracket [. To include a literal - character, it must be written first or last. Any character that does not have a defined special meaning inside a [] pair matches only itself.

mysql> SELECT REGEXP_LIKE('aXbc', '[a-dXYZ]');                 -> 1
mysql> SELECT REGEXP_LIKE('aXbc', '^[a-dXYZ]$');               -> 0
mysql> SELECT REGEXP_LIKE('aXbc', '^[a-dXYZ]+$');              -> 1
mysql> SELECT REGEXP_LIKE('aXbc', '^[^a-dXYZ]+$');             -> 0
mysql> SELECT REGEXP_LIKE('gheis', '^[^a-dXYZ]+$');            -> 1
mysql> SELECT REGEXP_LIKE('gheisa', '^[^a-dXYZ]+$');           -> 0

[=character_class=]

Within a bracket expression (written using [ and ]), [=character_class=] represents an equivalence class. It matches all characters with the same collation value, including itself. For example, if o and (+) are the members of an equivalence class, [[=o=]], [[=(+)=]], and [o(+)] are all synonymous. An equivalence class may not be used as an endpoint of a range.

[:character_class:]

Within a bracket expression (written using [ and ]), [:character_class:] represents a character class that matches all characters belonging to that class. The following table lists the standard class names. These names stand for the character classes defined in the ctype(3) manual page. A particular locale may provide other class names. A character class may not be used as an endpoint of a range.

mysql> SELECT REGEXP_LIKE('justalnums', '[[:alnum:]]+');       -> 1
mysql> SELECT REGEXP_LIKE('!!', '[[:alnum:]]+');               -> 0

The match engine uses memory for its internal stack. To control the maximum available memory for the stack in bytes, set the regexp_stack_limit system variable.

The match engine operates in steps. To control the maximum number of steps performed by the engine (and thus indirectly the execution time), set the regexp_time_limit system variable. Because this limit is expressed as number of steps, it affects execution time only indirectly. Typically, it is on the order of milliseconds.