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MySQL 5.6 Reference Manual  /  ...  /  Regular Expressions

12.5.2 Regular Expressions

Table 12.9 String Regular Expression Operators

REGEXP Pattern matching using regular expressions
RLIKE Synonym for REGEXP

A regular expression is a powerful way of specifying a pattern for a complex search.

MySQL uses Henry Spencer's implementation of regular expressions, which is aimed at conformance with POSIX 1003.2. MySQL uses the extended version to support pattern-matching operations performed with the REGEXP operator in SQL statements.

This section summarizes, with examples, the special characters and constructs that can be used in MySQL for REGEXP operations. It does not contain all the details that can be found in Henry Spencer's regex(7) manual page. That manual page is included in MySQL source distributions, in the regex.7 file under the regex directory. See also Section, “Pattern Matching”.

Regular Expression Operators

  • expr NOT REGEXP pat, expr NOT RLIKE pat

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

  • expr REGEXP pat, expr RLIKE pat

    Performs a pattern match of a string expression expr against a pattern pat. The pattern can be an extended regular expression, the syntax for which is discussed later in this section. Returns 1 if expr matches pat; otherwise it returns 0. If either expr or pat is NULL, the result is NULL. RLIKE is a synonym for REGEXP, provided for mSQL compatibility.

    The pattern need not be a literal string. For example, it can be specified as a string expression or table column.


    Because MySQL uses the C escape syntax in strings (for example, \n to represent the newline character), you must double any \ that you use in your REGEXP strings.

    REGEXP is not case sensitive, except when used with binary strings.

    mysql> SELECT 'Monty!' REGEXP '.*';
            -> 1
    mysql> SELECT 'new*\n*line' REGEXP 'new\\*.\\*line';
            -> 1
    mysql> SELECT 'a' REGEXP 'A', 'a' REGEXP BINARY 'A';
            -> 1  0
    mysql> SELECT 'a' REGEXP '^[a-d]';
            -> 1

    REGEXP and RLIKE use the character set and collations of the 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, “Collation of Expressions”.


    The REGEXP and RLIKE operators work in byte-wise fashion, so they are not multibyte safe and may produce unexpected results with multibyte character sets. In addition, these operators compare characters by their byte values and accented characters may not compare as equal even if a given collation treats them as equal.

Syntax of Regular Expressions

A regular expression describes a set of strings. The simplest regular expression is one that has no special characters in it. For example, the regular expression hello matches hello and nothing else.

Nontrivial regular expressions use certain special constructs so that they can match more than one string. For example, the regular expression hello|word matches either the string hello or the string word.

As a more complex example, the regular expression B[an]*s matches any of the strings Bananas, Baaaaas, Bs, and any other string starting with a B, ending with an s, and containing any number of a or n characters in between.

A regular expression for the REGEXP operator may use any of the following special characters and constructs:

  • ^

    Match the beginning of a string.

    mysql> SELECT 'fo\nfo' REGEXP '^fo$';                   -> 0
    mysql> SELECT 'fofo' REGEXP '^fo';                      -> 1
  • $

    Match the end of a string.

    mysql> SELECT 'fo\no' REGEXP '^fo\no$';                 -> 1
    mysql> SELECT 'fo\no' REGEXP '^fo$';                    -> 0
  • .

    Match any character (including carriage return and newline).

    mysql> SELECT 'fofo' REGEXP '^f.*$';                    -> 1
    mysql> SELECT 'fo\r\nfo' REGEXP '^f.*$';                -> 1
  • a*

    Match any sequence of zero or more a characters.

    mysql> SELECT 'Ban' REGEXP '^Ba*n';                     -> 1
    mysql> SELECT 'Baaan' REGEXP '^Ba*n';                   -> 1
    mysql> SELECT 'Bn' REGEXP '^Ba*n';                      -> 1
  • a+

    Match any sequence of one or more a characters.

    mysql> SELECT 'Ban' REGEXP '^Ba+n';                     -> 1
    mysql> SELECT 'Bn' REGEXP '^Ba+n';                      -> 0
  • a?

    Match either zero or one a character.

    mysql> SELECT 'Bn' REGEXP '^Ba?n';                      -> 1
    mysql> SELECT 'Ban' REGEXP '^Ba?n';                     -> 1
    mysql> SELECT 'Baan' REGEXP '^Ba?n';                    -> 0
  • de|abc

    Match either of the sequences de or abc.

    mysql> SELECT 'pi' REGEXP 'pi|apa';                     -> 1
    mysql> SELECT 'axe' REGEXP 'pi|apa';                    -> 0
    mysql> SELECT 'apa' REGEXP 'pi|apa';                    -> 1
    mysql> SELECT 'apa' REGEXP '^(pi|apa)$';                -> 1
    mysql> SELECT 'pi' REGEXP '^(pi|apa)$';                 -> 1
    mysql> SELECT 'pix' REGEXP '^(pi|apa)$';                -> 0
  • (abc)*

    Match zero or more instances of the sequence abc.

    mysql> SELECT 'pi' REGEXP '^(pi)*$';                    -> 1
    mysql> SELECT 'pip' REGEXP '^(pi)*$';                   -> 0
    mysql> SELECT 'pipi' REGEXP '^(pi)*$';                  -> 1
  • {1}, {2,3}

    {n} or {m,n} notation provides 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.

    • a*

      Can be written as a{0,}.

    • a+

      Can be written as a{1,}.

    • a?

      Can be written as a{0,1}.

    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.

    m and n must be in the range from 0 to RE_DUP_MAX (default 255), inclusive. If both m and n are given, m must be less than or equal to n.

    mysql> SELECT 'abcde' REGEXP 'a[bcd]{2}e';              -> 0
    mysql> SELECT 'abcde' REGEXP 'a[bcd]{3}e';              -> 1
    mysql> SELECT 'abcde' REGEXP '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 'aXbc' REGEXP '[a-dXYZ]';                 -> 1
    mysql> SELECT 'aXbc' REGEXP '^[a-dXYZ]$';               -> 0
    mysql> SELECT 'aXbc' REGEXP '^[a-dXYZ]+$';              -> 1
    mysql> SELECT 'aXbc' REGEXP '^[^a-dXYZ]+$';             -> 0
    mysql> SELECT 'gheis' REGEXP '^[^a-dXYZ]+$';            -> 1
    mysql> SELECT 'gheisa' REGEXP '^[^a-dXYZ]+$';           -> 0
  • [.characters.]

    Within a bracket expression (written using [ and ]), matches the sequence of characters of that collating element. characters is either a single character or a character name like newline. The following table lists the permissible character names.

    The following table shows the permissible character names and the characters that they match. For characters given as numeric values, the values are represented in octal.

    US037space' '
    mysql> SELECT '~' REGEXP '[[.~.]]';                     -> 1
    mysql> SELECT '~' REGEXP '[[.tilde.]]';                 -> 1
  • [=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.

    Character Class NameMeaning
    alnumAlphanumeric characters
    alphaAlphabetic characters
    blankWhitespace characters
    cntrlControl characters
    digitDigit characters
    graphGraphic characters
    lowerLowercase alphabetic characters
    printGraphic or space characters
    punctPunctuation characters
    spaceSpace, tab, newline, and carriage return
    upperUppercase alphabetic characters
    xdigitHexadecimal digit characters
    mysql> SELECT 'justalnums' REGEXP '[[:alnum:]]+';       -> 1
    mysql> SELECT '!!' REGEXP '[[:alnum:]]+';               -> 0
  • [[:<:]], [[:>:]]

    These markers stand for word boundaries. They match the beginning and end of words, respectively. A word is a sequence of word characters that is not preceded by or followed by word characters. A word character is an alphanumeric character in the alnum class or an underscore (_).

    mysql> SELECT 'a word a' REGEXP '[[:<:]]word[[:>:]]';   -> 1
    mysql> SELECT 'a xword a' REGEXP '[[:<:]]word[[:>:]]';  -> 0

To use a literal instance of a special character in a regular expression, precede it by two backslash (\) characters. The MySQL parser interprets one of the backslashes, and the regular expression library interprets the other. For example, to match the string 1+2 that contains the special + character, only the last of the following regular expressions is the correct one:

mysql> SELECT '1+2' REGEXP '1+2';                       -> 0
mysql> SELECT '1+2' REGEXP '1\+2';                      -> 0
mysql> SELECT '1+2' REGEXP '1\\+2';                     -> 1

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User Comments
  Posted by D. Meanea on May 30, 2003
If you are searching for literal parentheses, you have to enclose each parenthesis in brackets; otherwise, mySQL thinks they're part of the regular expression syntax. For instance:

WHERE phone REGEXP '(435)';

would return any phone numbers that have the sequence 435 in any part of the string, such as "1(801)555-4351". However:

WHERE phone REGEXP '[(]435[)]';

would return only phone numbers with (435), such as "1(435)555-5555".
  Posted by Marcello Alves on June 5, 2003
It's far beyond the scope of this documentation to dwell on all the gory details of regular expressions. Should you have any doubts, please refer to a good book on the subject like "Mastering Regular Expressions" ( References online include and
  Posted by a j stiles on November 3, 2003
The regular expression support in MySQL seems to be based on traditional-style regex (like ereg() in PHP), not the more sophisticated regular expression matching found in Perl or PHP's preg_match(). And in case the above doesn't make it clear (being mostly SELECT statements using the function directly to return a 1 or 0), you typically would use the REGEXP function in a WHERE clause like this:


To match a "special" character such as $, you need to prefix it with the backslash \ character. So \$ matches an actual dollar sign. However, in almost any programming language that claims a "C-like" syntax, that backslash is likely to get picked up on as a special character. So you may need to use an extra backslash. Also, at least in Perl and PHP, the $ is a special character itself, because it indicates that what follows is a variable name - so it will need a backslash too.

In Perl or PHP, you probably will write something like this to match on a line starting with a $ sign:

$query = "SELECT * FROM `foo` WHERE `bar` REGEXP \"^\\\$\""

I'll explain the special characters in that and what they mean:
backslash, speech mark = a literal speech mark
HAT sign = beginning of line
two backslashes = a literal backslash
backslash, dollar = a literal dollar sign
backslash, speech mark = a literal speech mark

Now if you print $query, it will have the value
SELECT * FROM `foo` WHERE `bar` REGEXP "^\$"
which is what you really want, and how you would type it into the mysql command line. Remember also that PHPMyAdmin expects you to put a backslash before a backslash or apostrophe. So in PHPMyAdmin you would enter
SELECT * FROM `foo` WHERE `bar` REGEXP "^\\$"

I guess if you only want to use . and .* regular expressions, you may as well stick to using LIKE with the _ and % wildcards, as that is probably a bit faster. Finally, when using regular expressions in *any* language you need to watch out, because it is very easy to write ones that will always match, and almost as easy to write ones that will never match anything. So do check!
  Posted by Vaz Aranni on June 30, 2005
Regexp's are pretty complicated. If you need anything more complicated than what's shown above, a good site to learn how to use them is The sites listed in the second comment are probably a good idea too.

Also, don't get in the habit of using character classes to escape metacharacters (like using [(] to match a literal parenthese). The open parentheses '(' and ')' have no special meaning inside a character class, but others like $ retain their meaning. Using [$] won't match the character '$', it'll still match the beginning of the string.

So escape them properly with backslashes.

So what if your PHP code has something that looks like...

mysql_query("select * from a where Name rlike '(^|//////|)example'")

...just to match a string that starts with "example" or contains the string "|example". It looks terrible and it works.
  Posted by Tony Boyd on October 12, 2005
For those of you struggling to escape special characters with long sequences of backslashes (see Vaz's post), I have to ask: why bother? Why not just use the dot-character syntax mentioned on this very page? For example, I needed to find all the ID attributes in some HTML. I tried escaping single and double-quotes for about 30 seconds, then I just switched to this:

SELECT * FROM site WHERE html REGEXP "id=[[.apostrophe.][.quotation-mark.]]archives[[.apostrophe.][.quotation-mark.]]";

Ta da. No escaping issues.
  Posted by Guido Dieterich on December 20, 2005
This sql statements:

SELECT 'WORD' REGEXP '[[:upper:]]{4}'; # => 1;
SELECT 'WORD' REGEXP '[[:lower:]]{4}'; # => 0
work right only when collate is _cs and NOT _ci (case insensitive)

created tables eg. the collate 'latin1_swedish_ci' have to be changed, if you want to use case sensitive REGEXPs like [[:upper:]] or [[:lower:]]!

I set in my.cnf now:
default-collation= latin1_general_cs

#default was latin1_swedish_ci
  Posted by Koy Kragh on March 4, 2006
The above post by Guido Dieterich (about collation and case sensitivity) is a good point. However, there is a way to match in a case-sensitive manner without having to change the collation of your existing tables: use the "BINARY" keyword.

Here's an extended example (based on the one previously posted):

('WORD' REGEXP '[[:upper:]]{4}') AS `upper_match`, # this will be a 1
('WORD' REGEXP '[[:lower:]]{4}') AS `lower_match`, # this will be a 1 on an "*_ci" collation
# -BINARY- matches below
(BINARY 'WORD' REGEXP '[[:upper:]]{4}') AS `bin_upper_match`, # this will be a 1
(BINARY 'WORD' REGEXP '[[:lower:]]{4}') AS `bin_lower_match` # this will be a 0 even on an "*_ci" collation
  Posted by Dennis K on November 8, 2006
The query "SELECT * FROM table WHERE text REGEXP 'UPPER'" on a *.ci (e.g. latin1_general_ci) table will find any case insensetive words, even words like "upper" or "uPpOr", or "UpPOr", etc...

To avoid this use one of the following Methods:

SELECT * FROM table WHERE text COLLATE latin1_general_cs REGEXP '...'



  Posted by richard versloot on May 9, 2007
information on boosting performance of regexp matching would be very welcome (for example: wich index type)
This information can't be find on the site.
  Posted by lvaro G. Vicario on October 10, 2007
"To use a literal instance of a special character in a regular expression, precede it by two backslash (\) characters."

If you are coding in PHP and you need to match a literal backslash you can easily end up with an unmaintainable mess of \\\\\\\\'s.

Try to keep it clean applying the appropriate escaping functions:


'^' preg_quote('one\\two') . '$';
$sql "SELECT * FROM my_table " .
"WHERE my_field REGEXP '" mysql_real_escape_string($match) . "'";


There doesn't seem to be a native quote funcion in MySQL but PHP's preg_quote() apparently works.
  Posted by Carl Longnecker on December 30, 2007
richard versloot-

regular expressions do not utilize indexes. the only way to improve their performance is to write a more efficient expression.
  Posted by Donoiu Cristian on July 3, 2008
Some of the next lines may be true:

-place the fixed/bigger part first or "fail fast", for ex: instead of (e|abcd) use (abcd|e)
-extract similitudes, ex: instead of (abcd|abef) use ab(cd|ef)
-prefere LIKE with % and _ , or string functions if the match is simple
-try to create less cycles(regex use a lot backtracking)!!!

Hope it helps!
  Posted by Alan Ng on November 7, 2009
I can't believe I'm the first to post this solution, since the pain of MySQL's REGEXP not working with multibyte character sets has been expressed all over the Web for years, I see.

Here's my simple workaround, for a database, server, and current connection that are entirely in UTF-8. Of course this only helps the majority of us developers who are in fact dealing with stored data that could just as well have be expressed in latin1:

SELECT * FROM YourTables WHERE (CONVERT (TextField USING latin1)) REGEXP CONVERT ('YourUTF8RegExp' USING latin1))

  Posted by Miklos Kokenyesi on November 30, 2009
Maybe this will be useful for others.
While creating a search function with syntax-highlighting for content which include bulletin board codes ([code], [ul], [li], etc.) I was stuck for a few hours about how to exclude the contents of the BBC tags. For example, if someone search for "ode", the [code] tags won't needed in the result list, not to mention that the syntax highlighting destroyed the html code as well :)

I was only able to do it this way ($search is the search string, passed from php):

WHERE LOWER(content) LIKE '%$search%'
AND content REGEXP '[\]].[^\[]*$search'

I wanted my $search to be found only after "]", and only if there is no "[" between them. Other characters are allowed.
  Posted by Jim W on July 13, 2010
Since character code escape sequences aren't supported, here's a handy regexp for finding any rows with characters outside of the ASCII range:

SELECT * FROM my_table
WHERE the_column REGEXP '[^[.NUL.]-[.DEL.]]'

Alternately, if you want to exclude control characters as well:

SELECT * FROM my_table
WHERE the_column REGEXP '[^ -~]'
  Posted by ehab heikal on September 21, 2010
For those times when you need a fast reference for regex you can download and print or view this pdf .

The sheet is color coded and is very easy to read.
  Posted by Kasey Speakman on November 10, 2010
It's quite unfortunate that their REGEX interpreter doesn't support logical NOT expressions. Ordinarily I would write something like this to match all numbers except 11:


But with their implementation, I have to make a "do not match" field as well as a "match" field to make sure my conditions are met. :/
  Posted by Andrey Klyuchnikov on March 1, 2011
re: Kasey Speakman


  Posted by Naved Shah on May 13, 2011
For LIKE Results



  Posted by Jon Spriggs on November 24, 2011
I struggled with the [:character_type:] element of the regexp. I had a problem where users were entering artist names with various degrees of spacing in the name... for example "Loudog" and "Lou Dog".

To get around this, I changed the string being searched for, in code, to: "[:space:]*L[:space:]*o[:space:]*u[:space:]*D[:space:]*o[:space:]*g[:space:]*" but this wasn't working.

Eventually someone spotted that I was essentially searching for zero-or-more instances of the characters :, s, p, a, c or e. This search should instead have been: "[[:space:]]*L[[:space:]]*o[[:space:]]*u[[:space:]]*D[[:space:]]*o[[:space:]]*g[[:space:]]*"

It's not clear in the examples above that this is what you should be searching for. This is roughly equivelent to "/\s+L\s+o\s+u\s+D\s+o\s+g\s+/i"

  Posted by Kasey Speakman on December 8, 2011
@Andrey Klyuchnikov

Using ORed decompositions is fine for my simple example, but in actual data, the length of the decompositions may be well beyond the point where they would be worth doing over just using two fields... or better yet if MySQL would implement the negation operator ?!.

Also, decompositions are much less clear in what they are doing. It's pretty obvious what the negation operator is doing. When I have to revisit a regex 2 years from now to add something to it, I'm going to want to smack someone that used a decomp.
  Posted by Eric Kent on December 23, 2011
If you need an IsNumeric or IsInt function, you can use:
return sValue regexp '^-?[0-9]+[.]?[0-9]*$|^-?[.][0-9]+$';
return sValue regexp '^-?[0-9]+$';
where sValue is a char argument.
  Posted by Naftali Zakharov on May 2, 2013
Ehab Heikal, thanks for your link to the regex cheat sheet. Only, the content is no longer there. I am aware of some other regex cheat sheets that seem very popular and I am sharing a short list here.

1) A pretty neutral cheat sheet for regexes.
The download is for free.
and there is a nicer-looking one for a symbolic fee, here:

2) While we are at it, here's a MySQL cheat sheet by the same author:

3) Another regex cheat sheet:

Hope this is helpful.
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