TSQL Regular Expression Workbench（TSQL的正则表达式）

/* This Workbench is about using Regular expressions with SQL Server via TSQL. It doesn't even attempt to teach how regular expressions work or how to pull them together. There are plenty of such resources on the Web. The aim is to demonstrate a few possibilities and try to persuade you to experiment with them if you don't already use Regex with SQL Server. We suggest that, if you are an ordinary mortal like Phil or I, without special powers, you should use an application such as RegexBuddy to form, edit and interpret Regular expressions. It makes learning them a lot easier. In order that people with access only to SQL Server 2000 can use the workbench, we'll use OLE in the examples, but they are readily adapted to CLR As always, the source code is in the speechbubble above. *//*-- Contents --IntroductionThe OLE FunctionsThe OLE Regex Match functionThe OLE Regex Replace functionThe OLE Regex Find (Execute) functionCombining two RegexsOLE Regex PerformanceRegular Expressions can be very useful to the Database programmer, particularly for data validation, data feeds and data transformations. A lot of the time, tools such as grep and awk or Funduc's S&R will be the most suitable way of using regular expressions, but just occasionally, it is handy to be able to use them in TSQL as we'll try to show.Regular Expressions are not regular in the sense that there is any common dialect of expression that is understood by all Regex engines. On the contrary, regular expresssions aren't always portable and there are many common, similar but incompatible, dialects in use, such as Perl 5.8, Java.util.regex, .NET, PHP, Python, Ruby, ECMA Javascript, PCRE, Apache, vi, Shell tools TCL ARE, POSIX BRE, Funduc and JGsoft.Regular Expressions were never developed to be easy to understand. They are a condensed shorthand that, on preliminary inspection, looks as if someone has repeatedly sat on the keyboard. Even when interpreted, the logic isn't always easy to follow. If you don't agree, then explain this one!Probably the best tutorial on the web for Regular Expressions is on www.regular-expressions.info but it is also worth reading Implementing Real-World Data Input Validation using Regular Expressions by Francis Norton for an introduction to regular expressionsA great deal can be done using commandline applications that work with regular expressions such as GREP and AWK. However, there are times where it is handy to use Regex directly from TSQL. There are two Regex engines available to SQL Server. These arethe .NET Regex which is in the system.text.regularexpression moduleThe ECMA Regex from VBScript.RegExp which is distributed with the IE browser and is used by Javascript and JScript.Both of these are excellent standard implementations. Both work well in TSQL.The .NET Regex requires the creation of CLR functions to provide regular expressions, and works only with SQL Server 2005, (and 2007) See CLR Integration by Christoffer HedgateThe ECMA Regex can be used via VBScript.RegExp, which are available to SQL Server 2000 as well. The regex is compatible with Javascript.The advantage of using CLR is that the regular expressions of the NET framework are very good, and performance is excellent. However, the techniques are well-known, whereas some of the more powerful uses of VBScript.RegExp have hardly ever been published, so this workbench will concentrate on the latterThe OLE functions------------------There are various properties to consider in these functionsIgnoreCaseBy default, the regular expression is case sensitive. In the following functions, we have set the IgnoreCase property to True to make it case insensitive.The Multiline propertyThe caret and dollar only match at the very start and very end of the subject string by default. If your subject string consists of multiple lines separated by line breaks, you can make the caret and dollar match at the start and the end of those lines by setting the Multiline property to True. (there is no option to make the dot match line break characters).The Global propertyIf you want the RegExp object to return or replace all matches instead of just the first one, set the Global property to True.Only the 'IgnoreCase is relevant in the first function but we've 'hardcoded' it to 1 as case-sensitive searches are a minority interest.The OLE Regex Match function-----------------------------Let's start off with something simple, a function for testing a string against a regular expression */IF OBJECT_ID (N'dbo.RegexMatch') IS NOT NULL   DROP FUNCTION dbo.RegexMatchGOCREATE FUNCTION dbo.RegexMatch    (      @pattern VARCHAR(2000),      @matchstring VARCHAR(MAX)--Varchar(8000) got SQL Server 2000    )RETURNS INT/* The RegexMatch returns True or False, indicating if the regular expression matches (part of) the string. (It returns null if there is an error).When using this for validating user input, you'll normally want to check if the entire string matches the regular expression. To do so, put a caret at the start of the regex, and a dollar at the end, to anchor the regex at the start and end of the subject string.*/ AS BEGIN    DECLARE @objRegexExp INT,        @objErrorObject INT,        @strErrorMessage VARCHAR(255),        @hr INT,        @match BIT    SELECT  @strErrorMessage = 'creating a regex object'    EXEC @hr= sp_OACreate 'VBScript.RegExp', @objRegexExp OUT    IF @hr = 0         EXEC @hr= sp_OASetProperty @objRegexExp, 'Pattern', @pattern        --Specifying a case-insensitive match     IF @hr = 0         EXEC @hr= sp_OASetProperty @objRegexExp, 'IgnoreCase', 1        --Doing a Test'     IF @hr = 0         EXEC @hr= sp_OAMethod @objRegexExp, 'Test', @match OUT, @matchstring    IF @hr <> 0         BEGIN            RETURN NULL        END    EXEC sp_OADestroy @objRegexExp    RETURN @match   ENDGO/* Now, with this routine, we can do some complex input validation*/--IS there a repeating wordSELECT dbo.RegexMatch('\b(\w+)\s+\1\b','this has has been repeated')--1SELECT dbo.RegexMatch('\b(\w+)\s+\1\b','this has not been repeated')--0--find a word near another word (in this case 'for' and 'last' 1 or 2 words apart)SELECT dbo.RegexMatch('\bfor(?:\W+\w+){1,2}?\W+last\b',           'You have failed me for the last time, Admiral')--1SELECT dbo.RegexMatch('\bfor(?:\W+\w+){1,2}?\W+last\b',           'You have failed me for what could be the last time, Admiral')--0--is this likely to be a valid credit cardSELECT dbo.RegexMatch('^(?:4[0-9]{12}(?:[0-9]{3})?|5[1-5][0-9]{14}|6011[0-9]{12}|3(?:0[0-5]|[68][0-9])[0-9]{11}|3[47][0-9]{13}|(?:2131|1800)\d{11})$','4953129482924435')          --IS this a valid ZIP codeSELECT dbo.RegexMatch('^[0-9]{5,5}([- ]?[0-9]{4,4})?$','02115-4653')--is this a valid PostcodeSELECT dbo.RegexMatch('^([Gg][Ii][Rr] 0[Aa]{2})|((([A-Za-z][0-9]{1,2})|(([A-Za-z][A-Ha-hJ-Yj-y][0-9]{1,2})|(([A-Za-z][0-9][A-Za-z])|([A-Za-z][A-Ha-hJ-Yj-y][0-9]?[A-Za-z])))) {0,1}[0-9][A-Za-z]{2})$','RG35 2AQ')--is this a valid European dateSELECT dbo.RegexMatch('^((((31\/(0?[13578]|1[02]))|((29|30)\/(0?[1,3-9]|1[0-2])))\/(1[6-9]|[2-9]\d)?\d{2})|(29\/0?2\/(((1[6-9]|[2-9]\d)?(0[48]|[2468][048]|[13579][26])|((16|[2468][048]|[3579][26])00))))|(0?[1-9]|1\d|2[0-8])\/((0?[1-9])|(1[0-2]))\/((1[6-9]|[2-9]\d)?\d{2})) (20|21|22|23|[0-1]?\d):[0-5]?\d:[0-5]?\d$','12/12/2007 20:15:27')--is this a valid currency value (dollar)SELECT dbo.RegexMatch('^\$(\d{1,3}(\,\d{3})*|(\d+))(\.\d{2})?$','$34,000.00')--is this a valid currency value (Sterling)SELECT dbo.RegexMatch('^\£(\d{1,3}(\,\d{3})*|(\d+))(\.\d{2})?$','£34,000.00')--A valid email address?SELECT dbo.RegexMatch('^(([a-zA-Z0-9!#\$%\^&\*\{\}''`\+=-_\|/\?]+(\.[a-zA-Z0-9!#\$%\^&\*\{\}''`\+=-_\|/\?]+)*){1,64}@(([A-Za-z0-9]+[A-Za-z0-9-_]*){1,63}\.)*(([A-Za-z0-9]+[A-Za-z0-9-_]*){3,63}\.)+([A-Za-z0-9]{2,4}\.?)+){1,255}$','[e-mail]')/*With this function, the passing back of errors is rudimentary. If an OLE error occurs, then a null is passed back.There are two other basic Regex functions available. With them, you can use regular expressions in all sorts of places in TSQL without having to get to direct grips with the rather awkward OLE interface.The OLE Regex Replace function-----------------------------*/IF OBJECT_ID(N'dbo.RegexReplace') IS NOT NULL     DROP FUNCTION dbo.RegexReplaceGOCREATE FUNCTION dbo.RegexReplace    (      @pattern VARCHAR(255),      @replacement VARCHAR(255),      @Subject VARCHAR(MAX),      @global BIT = 1,     @Multiline bit =1    )RETURNS VARCHAR(MAX)/*The RegexReplace function takes three string parameters. The pattern (the regular expression) the replacement expression, and the subject string to do the manipulation to.The replacement expression is one that can cause difficulties. You can specify an empty string '' as the @replacement text. This will cause the Replace method to return the subject string with all regex matches deleted from it (see "strip all HTML elements out of a string" below). To re-insert the regex match as part of the replacement, include $& in the replacement text. (see "find a #comment and add a TSQL --" below)If the regexp contains capturing parentheses, you can use backreferences in the replacement text. $1 in the replacement text inserts the text matched by the first capturing group, $2 the second, etc. up to $9. (e.g. see import delimited text into a database below) To include a literal dollar sign in the replacements, put two consecutive dollar signs in the string you pass to the Replace method.*/AS BEGIN    DECLARE @objRegexExp INT,        @objErrorObject INT,        @strErrorMessage VARCHAR(255),        @Substituted VARCHAR(8000),        @hr INT,        @Replace BIT    SELECT  @strErrorMessage = 'creating a regex object'    EXEC @hr= sp_OACreate 'VBScript.RegExp', @objRegexExp OUT    IF @hr = 0         SELECT  @strErrorMessage = 'Setting the Regex pattern',                @objErrorObject = @objRegexExp    IF @hr = 0         EXEC @hr= sp_OASetProperty @objRegexExp, 'Pattern', @pattern    IF @hr = 0 /*By default, the regular expression is case sensitive. Set the IgnoreCase property to True to make it case insensitive.*/        SELECT  @strErrorMessage = 'Specifying the type of match'     IF @hr = 0         EXEC @hr= sp_OASetProperty @objRegexExp, 'IgnoreCase', 1    IF @hr = 0         EXEC @hr= sp_OASetProperty @objRegexExp, 'MultiLine', @Multiline    IF @hr = 0         EXEC @hr= sp_OASetProperty @objRegexExp, 'Global', @global    IF @hr = 0         SELECT  @strErrorMessage = 'Doing a Replacement'     IF @hr = 0         EXEC @hr= sp_OAMethod @objRegexExp, 'Replace', @Substituted OUT,            @subject, @Replacement     /*If the RegExp.Global property is False (the default), Replace will return the @subject string with the first regex match (if any) substituted with the replacement text. If RegExp.Global is true, the @Subject string will be returned with all matches replaced.*/       IF @hr <> 0         BEGIN            DECLARE @Source VARCHAR(255),                @Description VARCHAR(255),                @Helpfile VARCHAR(255),                @HelpID INT               EXECUTE sp_OAGetErrorInfo @objErrorObject, @source OUTPUT,                @Description OUTPUT, @Helpfile OUTPUT, @HelpID OUTPUT            SELECT  @strErrorMessage = 'Error whilst '                    + COALESCE(@strErrorMessage, 'doing something') + ', '                    + COALESCE(@Description, '')            RETURN @strErrorMessage        END    EXEC sp_OADestroy @objRegexExp    RETURN @Substituted   ENDGO--remove repeated words in textSELECT  dbo.RegexReplace('\b(\w+)(?:\s+\1\b)+', '$1',                         'Sometimes I cant help help help stuttering',1, 1)--find a #comment and add a TSQL --SELECT  dbo.RegexReplace('#.*','--$&','# this is a commentfirst,second,third,fourth',1,1)--replace a url with an HTML anchorSELECT  dbo.RegexReplace(        '\b(https?|ftp|file)://([-A-Z0-9+&@#/%?=~_|!:,.;]*[-A-Z0-9+&@#/%=~_|])',        '<a href="$2">$2</a>',         'There is  this amazing site at http://www.simple-talk.com',1,1)--strip all HTML elements out of a stringSELECT  dbo.RegexReplace('<(?:[^>''"]*|([''"]).*?\1)*>',   '','<a href="http://www.simple-talk.com">Simle Talk is wonderful</a><!--This is a comment --> we all love it',1,1)--import delimited text into a database, converting it into insert statementsSELECT  dbo.RegexReplace( '([^\|\r\n]+)[|\r\n]+([^\|\r\n]+)[|\r\n]+([^\|\r\n]+)[|\r\n]+([^\|\r\n]+)[|\r\n]+', 'Insert into MyTable (Firstcol,SecondCol, ThirdCol, Fourthcol)select $1,$2,$3,$4','1|white gloves|2435|245652|Sports Shoes|285678|09873|Stumps|2845|9874|bat|29862|4875',1,1)/**/The OLE Regex Find (Execute) function-----------------------------This is the most powerful function for doing complex finding and replacing of text. As it passes back detailed records of the hits, including the location and the backreferences, it allows for complex manipulations.This is written as a table function. The Regex Routine actually passes back a collection for each 'hit'. In the relational world, you'd normally represent this in two tables, so we've returned a left outer join of the two logical tables so as to pass back all the information. This seems to cater for all the uses we can think of. We also append an error column, which should be blank!*/IF OBJECT_ID(N'dbo.RegexFind') IS NOT NULL     DROP FUNCTION dbo.RegexFindGOCREATE FUNCTION RegexFind(    @pattern VARCHAR(255),    @matchstring VARCHAR(MAX),    @global BIT = 1,   @Multiline bit =1)RETURNS    @result TABLE        (        Match_ID INT,          FirstIndex INT ,          length INT ,          Value VARCHAR(2000),          Submatch_ID INT,          SubmatchValue VARCHAR(2000),         Error VARCHAR(255)        )AS -- columns returned by the function   BEGIN    DECLARE @objRegexExp INT,        @objErrorObject INT,        @objMatch INT,        @objSubMatches INT,        @strErrorMessage VARCHAR(255),       @error VARCHAR(255),        @Substituted VARCHAR(8000),        @hr INT,        @matchcount INT,        @SubmatchCount INT,        @ii INT,        @jj INT,        @FirstIndex INT,        @length INT,        @Value VARCHAR(2000),        @SubmatchValue VARCHAR(2000),        @objSubmatchValue INT,        @command VARCHAR(8000),        @Match_ID INT            DECLARE @match TABLE        (          Match_ID INT IDENTITY(1, 1)                       NOT NULL,          FirstIndex INT NOT NULL,          length INT NOT NULL,          Value VARCHAR(2000)        )        DECLARE @Submatch TABLE        (          Submatch_ID INT IDENTITY(1, 1),          match_ID INT NOT NULL,          SubmatchNo INT NOT NULL,          SubmatchValue VARCHAR(2000)        )           SELECT  @strErrorMessage = 'creating a regex object',@error=''    EXEC @hr= sp_OACreate 'VBScript.RegExp', @objRegexExp OUT    IF @hr = 0         SELECT  @strErrorMessage = 'Setting the Regex pattern',                @objErrorObject = @objRegexExp    IF @hr = 0         EXEC @hr= sp_OASetProperty @objRegexExp, 'Pattern', @pattern    IF @hr = 0         SELECT  @strErrorMessage = 'Specifying a case-insensitive match'     IF @hr = 0         EXEC @hr= sp_OASetProperty @objRegexExp, 'IgnoreCase', 1    IF @hr = 0         EXEC @hr= sp_OASetProperty @objRegexExp, 'MultiLine', @Multiline    IF @hr = 0         EXEC @hr= sp_OASetProperty @objRegexExp, 'Global', @global    IF @hr = 0         SELECT  @strErrorMessage = 'Doing a match'     IF @hr = 0         EXEC @hr= sp_OAMethod @objRegexExp, 'execute', @objMatch OUT,            @matchstring    IF @hr = 0         SELECT  @strErrorMessage = 'Getting the number of matches'         IF @hr = 0         EXEC @hr= sp_OAGetProperty @objmatch, 'count', @matchcount OUT    SELECT  @ii = 0     WHILE @hr = 0        AND @ii < @Matchcount        BEGIN/*The Match object has four read-only properties. The FirstIndex property indicates the number of characters in the string to the left of the match. The Length property of the Match object indicates the number of characters in the match. The Value property returns the text that was matched.*/            SELECT  @strErrorMessage = 'Getting the FirstIndex property',                    @command = 'item(' + CAST(@ii AS VARCHAR) + ').FirstIndex'                IF @hr = 0                 EXEC @hr= sp_OAGetProperty @objmatch, @command,                    @Firstindex OUT            IF @hr = 0                 SELECT  @strErrorMessage = 'Getting the length property',                        @command = 'item(' + CAST(@ii AS VARCHAR) + ').Length'                IF @hr = 0                 EXEC @hr= sp_OAGetProperty @objmatch, @command, @Length OUT            IF @hr = 0                 SELECT  @strErrorMessage = 'Getting the value property',                        @command = 'item(' + CAST(@ii AS VARCHAR) + ').Value'                IF @hr = 0                 EXEC @hr= sp_OAGetProperty @objmatch, @command, @Value OUT            INSERT  INTO @match                    (                      Firstindex,                      [Length],                      [Value]                    )                    SELLECT  @firstindex + 1,                            @Length,                            @Value            SELECT  @Match_ID = @@Identity         /*The SubMatches property of the Match object is a collection of strings. It will only hold values if your regular expression has capturing groups. The collection will hold one string for each capturing group. The Count property (returned as SubmatchCount) indicates the number of string in the collection. The Item property takes an index parameter, and returns the text matched by the capturing group. */            IF @hr = 0                 SELECT  @strErrorMessage = 'Getting the SubMatches collection',                        @command = 'item(' + CAST(@ii AS VARCHAR)                        + ').SubMatches'                IF @hr = 0                 SELECT  @strErrorMessage = 'Getting the number of submatches'                 IF @hr = 0                 EXEC @hr= sp_OAGetProperty @objSubmatches, 'count',                    @submatchCount OUT            SELECT  @jj = 0             WHILE @hr = 0                AND @jj < @submatchCount                BEGIN                    IF @hr = 0                         SELECT  @strErrorMessage = 'Getting the submatch value property',                                @command = 'item(' + CAST(@jj AS VARCHAR)                                + ')' ,@submatchValue=NULL                       IF @hr = 0                         EXEC @hr= sp_OAGetProperty @objSubmatches, @command,                            @SubmatchValue OUT                    INSERT  INTO @Submatch                            (                              Match_ID,                              SubmatchNo,                              SubmatchValue                            )                            SELECT  @Match_ID,                                    @jj+1,                                    @SubmatchValue                    SELECT  @jj = @jj + 1                END                   EXEC @hr= sp_OAGetProperty @objmatch, @command,                    @objSubmatches OUT                 SELECT  @ii = @ii + 1        END    IF @hr <> 0         BEGIN            DECLARE @Source VARCHAR(255),                @Description VARCHAR(255),                @Helpfile VARCHAR(255),                @HelpID INT               EXECUTE sp_OAGetErrorInfo @objErrorObject, @source OUTPUT,                @Description OUTPUT, @Helpfile OUTPUT, @HelpID OUTPUT            SELECT  @Error = 'Error whilst '                    + COALESCE(@strErrorMessage, 'doing something') + ', '                    + COALESCE(@Description, '')        END    EXEC sp_OADestroy @objRegexExp     EXEC sp_OADestroy        @objMatch     EXEC sp_OADestroy        @objSubMatchesINSERT INTO @result          (Match_ID,          FirstIndex,          [length],          [Value],          Submatch_ID,          SubmatchValue,         error)    SELECT  m.[Match_ID],           [FirstIndex],           [length],           [Value],[SubmatchNo],           [SubmatchValue],@error  FROM    @match m    LEFT OUTER JOIN   @submatch s    ON m.match_ID=s.match_ID    IF @@rowcount=0 AND LEN(@error)>0INSERT INTO @result(error) SELECT @errorRETURN ENDGO--showing the context where two words 'for' and 'last' are found in proximityDECLARE @sample VARCHAR(2000)SELECT @Sample='You have failed me for the last time, Admiral.We have not long to wait for your last gasp'SELECT '...'+SUBSTRING(@Sample,Firstindex-8,length+16)+'...'     FROM dbo.RegexFind ('\bfor(?:\W+\w+){0,3}?\W+last\b',           @sample,1,1)--finding repeated words, showing the repetition and the repeated word SELECT [repetition]=value, [word]=SubmatchValue FROM dbo.RegexFind ('\b(\w+)\s+\1\b','this this is is a repeated word word word',1,1)--Split lines based on a regular expressionSELECT value FROM dbo.regexfind('[^\r\n]*(?:[\r\n]*)','This is the second lineThis is the thirdand the fourth',1,1) WHERE length>0--break up all words in a string into separate table rowsSELECT value FROM dbo.RegexFind ('\b[\w]+\b','Hickory dickory dock, the mouse ran up the clock',1,1)--split text into keywords and valuesSELECT Match_ID, [keyword]=MAX (CASE WHEN submatch_ID=1 THEN  submatchValue ELSE '' END),[value]=MAX (CASE WHEN submatch_ID=2 THEN  submatchValue ELSE '' END)  FROM dbo.RegexFind ('(\w+)\s*=\s*(.*)\s*','firstname=PhilLastname=FactorSalary=$200,000age=unknown to usPost=DBA',1,1) GROUP BY Match_IDSELECT * FROM dbo.RegexFind ('([^\|\r\n]+[\|\r\n]+)','1|white gloves|2435|245652|Sports Shoes|285678|09873|Stumps|2845|9874|bat|29862|4875',1,1)--get valid dates and convert to SQL Server formatSELECT DISTINCT CONVERT(DATETIME,value,103) FROM dbo.RegexFind ('\b(0?[1-9]|[12][0-9]|3[01])[- /.](0?[1-9]|1[012])[- /.](19|20?[0-9]{2})\b','12/2/2006 12:30 <> 13/2/200732/3/20072-4-200725.8.20071/1/200534/2/21042/5/2006',1,1)/*Combining two Regexs--------------------Once you've experimented with the regex calls we've provided, you'll realise that you can create some really cool functions and procedures that combine regexs. Here we have a procedure that does a 'google-style' search on text to find the words you specify. It returns the 'context' in that it quotes the substring where the match occurred. You can specify how close the words need to be to specify a 'hit'*/IF OBJECT_ID(N'dbo.FindWordsInContext') IS NOT NULL     DROP FUNCTION dbo.FindWordsInContextGOCREATE FUNCTION dbo.FindWordsInContext    (      @words VARCHAR(255),--list of words you want searched for      @text VARCHAR(MAX),--the text you want searched       @proximity INT--the maximum distance in words between specified words    )RETURNS @proximityList TABLE    (      Hit INT IDENTITY(1, 1),      context VARCHAR(2000)    )AS BEGIN    DECLARE @Pattern VARCHAR(512)    SELECT  @Pattern = COALESCE(@pattern + '(?:\W+\w+){0,'                                + CAST(@proximity AS VARCHAR(5)) + '}?\W+',                                '\b') + value    FROM    dbo.RegexFind('\b[\w]+\b', @words, 1, 1)    INSERT  INTO @ProximityList ( context )            SELECT  '...' + SUBSTRING(@text, Firstindex - 8, length + 16)                    + '...'            FROM    dbo.RegexFind(@pattern+'\b', @text, 1, 1)    RETURN   ENDGOSELECT * FROM dbo.FindWordsInContext('sadness farewell embark','Sunset and evening star,And one clear call for me!And may there by no moaning of the bar,When I put out to sea,But such a tide as moving seems asleep,Too full for sound and foam,When that which drew from out the boundless deepTurns again home. Twilight and evening bell,And after that the dark!And may there be no sadness of farewell,When I embark; For tho'' from out our bourne of Time and PlaceThe flood may bear me far,I hope to see my Pilot face to faceWhen I have crost the bar. ',8)/*OLE Regex performance-----------------Whereas the use of the OLE VBScript.RegExp to scan large chunks of text is fine, it is good for complex validation, and it makes a great testbed for regexes, These OLE functions are too slow for use in queries. The overhead of making the calls is just too high because the performance of OLE in TSQL is not great. See Zach Nichter's excellent article on the subject 'Writing to a File Using the sp_OACreate Stored Procedure and OSQL' Here is an example, scanning a databases of nearly 50,000 names of public houses from out XML Jumpstart Workbench.*/SELECT COUNT(*) FROMpublichouses.dbo.publichouses WHERE dbo.RegexMatch ('\bred\b',name)=1--5 minutes 28 secsSELECT COUNT(*) FROM publichouses.dbo.publichouses WHERE name LIKE '%red %'--less than 50 ms/*You can reduce the overhead to a quarter of what it was by using a function like this and creating the Regex object before you do the call. This means the Regex Object does not get repeatedly created and destroyed on every call.*/IF OBJECT_ID(N'dbo.OARegexMatch') IS NOT NULL     DROP FUNCTION dbo.OARegexMatchGOCREATE FUNCTION dbo.OARegexMatch /* very simple Function Wrapper around the call */    (     @objRegexExp INT,      @matchstring VARCHAR(MAX)    )RETURNS INTAS BEGIN    DECLARE @objErrorObject INT,        @hr INT,        @match BIT        EXEC @hr= sp_OAMethod @objRegexExp, 'Test', @match OUT, @matchstring    IF @hr <> 0         BEGIN            RETURN NULL        END    RETURN @match   ENDGO/* and now embed the SQL Query within the life-cycle of the Regex object */DECLARE @objRegexExp INT,        @objErrorObject INT,        @strErrorMessage VARCHAR(255),        @hr INT,        @match BIT    SELECT  @strErrorMessage = 'creating a regex object'    EXEC @hr= sp_OACreate 'VBScript.RegExp', @objRegexExp OUT    IF @hr = 0         EXEC @hr= sp_OASetProperty @objRegexExp,'pattern', '\bred\b'        --Specifying a case-insensitive match     IF @hr = 0         EXEC @hr= sp_OASetProperty @objRegexExp, 'IgnoreCase', 1        --Doing a Test'     IF @hr = 0        SELECT COUNT(*)            FROM publichouses.dbo.publichouses            WHERE dbo.OARegexMatch (@objRegexExp,name)=1    IF @hr <> 0         BEGIN            DECLARE @Source VARCHAR(255),                @Description VARCHAR(255),                @Helpfile VARCHAR(255),                @HelpID INT               EXECUTE sp_OAGetErrorInfo @objErrorObject, @source OUTPUT,                @Description OUTPUT, @Helpfile OUTPUT, @HelpID OUTPUT            SELECT  @strErrorMessage = 'Error whilst '                    + COALESCE(@strErrorMessage, 'doing something') + ', '                    + COALESCE(@Description, '')            RAISERROR( @strErrorMessage,16,1)        END    EXEC sp_OADestroy @objRegexExp--1 minute 28 secs/* it is no consolation for those who are stuck with SQL Server 2000, but the CLR functions are a lot quicker for this sort of usage. */

We've used a range of regex patterns from a number of sources in this workbench. Like a lot of programmers, we collect up snippets we come across, almost always forgetting to record the original author. We therefore apologise in advance for not crediting the source and original author, of regex patterns. As you can guess, they often take a long time and effort to develop. If you spot a regex which we should have cited, please add a comment and let us all know who originally wrote it!