I was wondering, if there is some way to shuffle the letters of a string in mysql/sql, i.e. something like the pseudocode: SELECT SHUFFLE('abcdef')?
Couldn't find any from http://dev.mysql.com/doc/refman/5.0/en/string-functions.html and searching for it just seems to find solutions for shuffling results, not a string.
Here you go:
DELIMITER //
DROP FUNCTION IF EXISTS shuffle //
CREATE FUNCTION shuffle(
v_chars TEXT
)
RETURNS TEXT
NOT DETERMINISTIC -- multiple RAND()'s
NO SQL
SQL SECURITY INVOKER
COMMENT ''
BEGIN
DECLARE v_retval TEXT DEFAULT '';
DECLARE u_pos INT UNSIGNED;
DECLARE u INT UNSIGNED;
SET u = LENGTH(v_chars);
WHILE u > 0
DO
SET u_pos = 1 + FLOOR(RAND() * u);
SET v_retval = CONCAT(v_retval, MID(v_chars, u_pos, 1));
SET v_chars = CONCAT(LEFT(v_chars, u_pos - 1), MID(v_chars, u_pos + 1, u));
SET u = u - 1;
END WHILE;
RETURN v_retval;
END;
//
DELIMITER ;
SELECT shuffle('abcdef');
See sqlfiddle.com for the output.
Tested successfully with mariadb 10.1 (mysql 5.6 equivalent)
Edit: this solution is for Microsoft SQL Server.
As it's not allowed to use RAND() in user defined function, we create a view to use it later in our shuffle function:
CREATE VIEW randomView
AS
SELECT RAND() randomResult
GO
The actual shuffle function is as following:
CREATE FUNCTION shuffle(#string NVARCHAR(MAX))
RETURNS NVARCHAR(MAX) AS
BEGIN
DECLARE #pos INT
DECLARE #char CHAR(1)
DECLARE #shuffeld NVARCHAR(MAX)
DECLARE #random DECIMAL(18,18)
WHILE LEN(#string) > 0
BEGIN
SELECT #random = randomResult FROM randomView
SET #pos = (CONVERT(INT, #random*1000000) % LEN(#string)) + 1
SET #char = SUBSTRING(#string, #pos, 1)
SET #shuffeld = CONCAT(#shuffeld, #char)
SET #string = CONCAT(SUBSTRING(#string, 1, #pos-1), SUBSTRING(#string, #pos+1, LEN(#string)))
END
RETURN #shuffeld
END
Calling the function
DECLARE #string NVARCHAR(MAX) = 'abcdefghijklmnonpqrstuvwxyz0123456789!"ยง$%&/()='
SELECT dbo.shuffle(#string)
There is nothing in standard SQL - your best bet is probably to write a user defined function
Related
a MYSQL user defined function selects a row from a table. How does the UDF code determine if the selected row was found in the table?
CREATE FUNCTION snippetFolder_folderPath(folder_id int)
RETURNS varchar(512)
BEGIN
declare vFolder_id int;
declare vParent_id int;
declare vPath varchar(512) default '';
declare vFolderName varchar(256) default '';
set vFolder_id = folder_id;
build_path:
while (vFolder_id > 0) do
/* -------- how to know this select statement returns a row?? ---------- */
select a.parent_id, a.folderName
into vParent_id, vFolderName
from SnippetFolder a
where a.folder_id = vFolder_id;
if vPath = ' ' then
set vPath = vFolderName;
else
set vPath = concat_ws( '/', vFolderName, vPath );
end if ;
set vFolder_id = vParent_id;
end while ;
return vPath;
END
https://dev.mysql.com/doc/refman/8.0/en/select-into.html says:
If the query returns no rows, a warning with error code 1329 occurs (No data), and the variable values remain unchanged.
So you could declare a continue handler on warnings, something like the example from the documentation:
BEGIN
DECLARE i INT DEFAULT 3;
DECLARE done INT DEFAULT FALSE;
retry:
REPEAT
BEGIN
DECLARE CONTINUE HANDLER FOR SQLWARNING
BEGIN
SET done = TRUE;
END;
IF done OR i < 0 THEN
LEAVE retry;
END IF;
SET i = i - 1;
END;
UNTIL FALSE END REPEAT;
END
I'll leave it to you to read the documentation and adapt that example to your table and your loop.
Alternatively, if you're using MySQL 8.0 you can use recursive common table expression:
CREATE FUNCTION snippetFolder_folderPath(vFolder_id int)
RETURNS varchar(512)
BEGIN
DECLARE vPath varchar(512) DEFAULT '';
WITH RECURSIVE cte AS (
SELECT folderName, parent_id, 0 AS height
FROM SnippetFolder WHERE folder_id = vFolder_id
UNION
SELECT f.folderName, f.parent_id, cte.height+1
FROM SnippetFolder AS f JOIN cte ON cte.parent_id = f.folder_id
)
SELECT GROUP_CONCAT(folderName ORDER BY height DESC SEPARATOR '/')
INTO vPath
FROM cte;
RETURN vPath;
END
The recursive CTE result is all the ancestors of the row matching vFolder_id, and then one can use GROUP_CONCAT() to concatenate them together as one string.
I am having issues with a MySQL If statement that creates a group rank. here is the MySQL Statement:
SELECT EnCode, EnName, QuScore,
#scorerank := IF(#currathlete = EnCode, #scorerank + 1, 1),
#currathlete := EnCode
FROM ranking ORDER BY EnCode, QuScore DESC
It currently gives the following output
'1004277','Ashe','1628','1','1004277'
'1004277','Ashe','1309','1','1004277'
'1004277','Ashe','1263','1','1004277'
'1004277','Ashe','648','1','1004277'
'1004277','Ashe','645','1','1004277'
'1004277','Ashe','1628','1','1004277'
'1015934', 'Sabina', '544', '1', '1015934'
'1015934', 'Sabina', '455', '1', '1015934'
'1015934', 'Sabina', '276', '1', '1015934'
'1015934', 'Sabina', '216', '1', '1015934'
What it should be doing is incrementing each of the '1' numbers by one for each row that has the same code, and then starting from 1 again when it sees a different code number (1004277, then 1015934 in this case)
Any help is appreciated as i have followed a number of examples online using the above method but seem to hit the same issue a this point.
Try this way in stored Procedure:
drop PROCEDURE if EXISTS INCREMENTME;
create PROCEDURE INCREMENTME()
BEGIN
DECLARE OldEnNamevar VARCHAR(10) DEFAULT NULL;
DECLARE done INT DEFAULT FALSE;
DECLARE Encodevar VARCHAR(10);
DECLARE EnNamevar VARCHAR(10);
DECLARE QuScorevar VARCHAR(10);
DECLARE scorerankvar VARCHAR(10);
DECLARE currathalthletevar VARCHAR(10);
DECLARE countcode int(29) DEFAULT(1);
DECLARE counter int(20) default 0;
DECLARE get_cur CURSOR FOR select `Encode`,`EnName`,`QuScore`,`scorerank`,`currathalthlete` from tbl_ranking;
DECLARE CONTINUE HANDLER FOR SQLSTATE '02000' SET done=1;
drop table if exists temp_temptable;
create TEMPORARY table temp_temptable(Encodevar VARCHAR(50) NULL,EnNamevar VARCHAR(50) NULL,QuScorevar VARCHAR(50) NULL,scorerankvar VARCHAR(50) NULL,currathalthletevar VARCHAR(50) NULL,recordCount int(10) null);
OPEN get_cur;
REPEAT
set counter = counter + 1;
FETCH get_cur INTO Encodevar,EnNamevar,QuScorevar,scorerankvar,currathalthletevar;
if (OldEnNamevar = EnNamevar) THEN
set countcode = countcode +1;
ELSE
if(counter=1) then
set countcode = 1;
ELSE
set countcode = 0;
end if;
end if;
if (OldEnNamevar != EnNamevar) THEN
set countcode = 1;
end if;
if(OldEnNamevar=NULL) then
set countcode = 1;
end if;
insert into temp_temptable (Encodevar,EnNamevar,QuScorevar,scorerankvar,currathalthletevar,recordCount) values(Encodevar,EnNamevar,QuScorevar,scorerankvar,currathalthletevar,countcode);
set OldEnNamevar = EnNamevar;
UNTIL done END REPEAT;
select * from temp_temptable;
drop temporary table if exists temp_temptable;
CLOSE get_cur;
END
call the procedure like this:
call INCREMENTME();
Here's the result:
You have to initialize your variables, otherwise they are null (at least at the beginning of the session, probably not anymore if you run it twice), and your query will give strange results. Try
SELECT EnCode, EnName, QuScore,
#scorerank := IF(#currathlete = EnCode, #scorerank + 1, 1),
#currathlete := EnCode
FROM ranking, (select #currathlete := '', #scorerank := 0) init
ORDER BY EnCode, QuScore DESC
I'd like to know how I can create a MySQL function that declares 2 variables by using 1 select statement.
Something like this:
CREATE FUNCTION `inHashtagCampaign` (campaignId INT,startDateTime DATETIME,endDateTime DATETIME)
RETURNS TEXT
LANGUAGE SQL
DETERMINISTIC
BEGIN
DECLARE result TEXT;
DECLARE limit BIGINT(11);
DECLARE suspended TINYINT(1);
#
#I don't know how to do this, but I'd like to use the result of this query:
#
result = SELECT `limit`,`suspended` FROM `settings` WHERE `campaignId` = 2;
limit = result.limit;
suspended = result.suspended;
END;
I know this function is far from complete, but I'm kinda stuck on this thing already.
I think what you are trying to do is like this
DECLARE #limit BIGINT(11);
DECLARE #suspended TINYINT(1);
SELECT #limit := `limit`, #suspended := `suspended` FROM `settings`
WHERE `campaignId` = 2;
(OR)
DECLARE limit1 BIGINT(11);
DECLARE suspended1 TINYINT(1);
SELECT `limit`,`suspended` into limit1, suspended1
FROM `settings` WHERE `campaignId` = 2;
I have a long string.I want to check throughout this string for consecutive 15 letters if there is no space i have to manually put a space in sql server. Can any one pls help??
For eg. my string is 'ABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZ'
then it should appear like 'ABCDEFGHIJKLMNOP QRSTUVWXYZABCDE FGHIJKLMNOPQRST UVWXYZ'
#dcp1986: I tried with your function as below.
SELECT dbo.UF_StringSplitter('HeloEveryonehru Howslyfgoingonn HaveaGoodDayGoodMorning')
But an unexpected split occured. I think your function must be modified as below for the correct result:
IF EXISTS(SELECT * FROM sysobjects WHERE ID = OBJECT_ID('UF_StringSplitter'))
DROP FUNCTION UF_StringSplitter
GO
CREATE FUNCTION UF_StringSplitter (
#psCSString VARCHAR(MAX)
)
RETURNS VARCHAR(MAX)
AS
BEGIN
DECLARE #sTemp VARCHAR(MAX)
DECLARE #tTemp VARCHAR(MAX)
SET #tTemp=''
WHILE LEN(#psCSString)>15
BEGIN
SET #sTemp = LEFT(LTRIM(#psCSString), 15)
SET #psCSString = LTRIM(SUBSTRING(#psCSString,16, LEN(#psCSString)))
IF #psCSString LIKE ' %'
SET #tTemp=#tTemp+#sTemp
ELSE
SET #tTemp=#tTemp+#sTemp+' '
END
SET #tTemp=#tTemp+#psCSString
RETURN #tTemp
END
You could use a function like this
IF EXISTS(SELECT * FROM sysobjects WHERE ID = OBJECT_ID('UF_StringSplitter'))
DROP FUNCTION UF_StringSplitter
GO
CREATE FUNCTION UF_StringSplitter
(
#psCSString VARCHAR(MAX)
)
RETURNS VARCHAR(MAX)
AS
BEGIN
DECLARE #sTemp VARCHAR(MAX)
DECLARE #tTemp VARCHAR(MAX)
SET #tTemp=''
WHILE LEN(#psCSString)>15
BEGIN
SET #sTemp = LEFT(#psCSString, 15)
SET #psCSString = SUBSTRING(#psCSString,16, LEN(#psCSString))
IF #psCSString LIKE ' %'
SET #tTemp=#tTemp+#sTemp
ELSE
SET #tTemp=#tTemp+#sTemp+' '
END
SET #tTemp=#tTemp+#psCSString
RETURN #tTemp
END
Go
Here i have hard coded the splitting value, and you can use the function
UPDATE mytable SET mycol=dbo.UF_StringSplitter(mycol)
I don't know how to do it on a single statement, but you can create a sql function something like this
create function AddStuffCharacterInLength (#original nvarchar(100), #take int, #stuff varchar(100))
returns nvarchar(200)
AS
BEGIN
declare #result nvarchar(200)
declare #len int
declare #skip int
set #len = len(#original)
set #result = ''
set #skip = (#take * -1) + 1
while #len > 0
begin
set #result = #result + substring(#original, #skip + #take, #take)
set #len = #len - #take
set #skip = #skip + #take
if #len > 0
set #result = #result + ' '
end
RETURN #result
END
And use it like this
select dbo.AddStuffCharacterInLength ('ABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZ',15, ' ')
And the output should be
----------------------------------------------------------------------------------------------------
ABCDEFGHIJKLMNO PQRSTUVWXYZABCD EFGHIJKLMNOPQRS TUVWXYZ
(1 row(s) affected)
I'm working on a project involving C# and a SQL Server 2008 database.
In one of the tables, I have a field (nvarchar(15)) which will contain an IP address.
I'd like to add a check constraint which will validate that the input value is actually an IP address.
I wanted to use a regex to do that, but it seems that this feature is not supported by default. I saw things about writing a customm dll with UDF inside (MSDN tutorial), but I don't really understand how it works (i.e. where should I place the dll ?)
Is there a "simple" way to add such a constraint ?
Any solution is welcome.
Thanks in advance !
There are several way of doing this - the most performant one would probably be a CLR function in the database.
This is because SQL has fairly poor text manipulation tooling and no native RegEx in SQL Server.
As other have said, this is better handled by an application before insertion to the DB.
It shouldn't be handled in the database, it should be handled first and foremost in the application.
There's no harm in then adding a check to the database, but leaving it up to the DB to filter input is very sketchy.
The easiest way I can think of is to create a function like fnCheckIP and use this function in the constraint.
There's no need to use UDF.
create function fnCheckIP(#ip varchar(15)) returns bit
AS
begin
if (#ip is null)
return null
declare #num1 int
declare #num varchar(15)
declare #pos int
while (#ip is not null)
begin
set #pos = IsNull(NullIf(charindex('.', #ip), 0), Len(#ip) + 1)
set #num = substring(#ip, 1, #pos - 1)
if (isnumeric(#num) = 0) or (not cast(#num as int) between 0 and 255)
return cast(0 as bit)
if (len(#ip) - #pos <= 0)
set #ip = null
else
set #ip = NullIf(substring(#ip, #pos + 1, len(#ip) - #pos), '')
end
return cast (1 as bit)
end
go
select dbo.fnCheckIP('127.0.0.1')
select dbo.fnCheckIP('127.0.0.300')
This solution is similar to Paulo's but using either approach will require getting rid of the comma character because isnumeric allows commas which will throw a cast to int error.
CREATE FUNCTION fn_ValidateIP
(
#ip varchar(255)
)
RETURNS int
AS
BEGIN
DECLARE #Result int = 0
IF
#ip not like '%,%' and
len(#ip) <= 15 and
isnumeric(PARSENAME(#ip,4)) = 1 and
isnumeric(PARSENAME(#ip,3)) = 1 and
isnumeric(PARSENAME(#ip,2)) = 1 and
isnumeric(PARSENAME(#ip,1)) = 1 and
cast(PARSENAME(#ip,4) as int) between 1 and 255 and
cast(PARSENAME(#ip,3) as int) between 0 and 255 and
cast(PARSENAME(#ip,2) as int) between 0 and 255 and
cast(PARSENAME(#ip,1) as int) between 0 and 255
set #Result = 1
ELSE
set #Result = 0
RETURN #Result
END
select dbo.fn_ValidateIP('127.0.0.1')
This may not be entirely practical, but one way would be to store the converted string ###-###-###-### into a binary(4) data type. Let the interface fuss around with hyphens and deal with converting the four numbers to binary and back (and this could probably even be done by a caluclated column.) A bit extreme, yes, but with binary(4) you will always be able to turn it into an IP address.
At last about 10 yrs after Oracle, sqlserver got native compilation (with limitations)
ALTER function fn_ValidateIPv4
(
#ip varchar(255)
)
RETURNS int
--WITH EXECUTE AS OWNER, SCHEMABINDING, NATIVE_COMPILATION
AS
BEGIN
--ATOMIC WITH (TRANSACTION ISOLATION LEVEL = SNAPSHOT, LANGUAGE = N'us_english')
/* only sql2016 native Compilation **/
DECLARE #len_ip as int;
SET #len_ip = len(#ip);
DECLARE #firstBlock varchar(4) = '';
DECLARE #secondBlock varchar(4) = '';
DECLARE #thirdBlock varchar(4) = '';
DECLARE #fourthBlock varchar(4) = '';
DECLARE #countDot as smallint = 0;
DECLARE #l_i as smallint = 0;
DECLARE #l_curChar varchar(1) = 'X';
DECLARE #Result int = 0
IF (#len_ip <= 15)
BEGIN
WHILE (#l_i < #len_ip)
BEGIN
set #l_i += 1;
set #l_curChar = substring(#ip,#l_i,1);
if #l_curChar = '.'
SET #countDot += 1
ELSE
BEGIN
IF #l_curChar IN ( '0','1','2','3','4','5','6','7','8','9' )
BEGIN
IF #countDot = 0
SET #firstBlock = #firstBlock + #l_curChar;
IF #countDot = 1
SET #secondBlock = #secondBlock + #l_curChar;
IF #countDot = 2
SET #thirdBlock = #thirdBlock + #l_curChar;
IF #countDot = 3
SET #fourthBlock = #fourthBlock + #l_curChar;
IF #countDot > 3
set #firstBlock = 'AAA'; -- force error
END
ELSE set #firstBlock = 'AAA'; -- force error
END;
END;
IF ( #countDot = 3 and
cast(#fourthBlock as int) between 1 and 255 and
cast(#thirdBlock as int) between 0 and 255 and
cast(#secondBlock as int) between 0 and 255 and
cast(#firstBlock as int) between 0 and 255
)
set #Result = 1;
END;
/*
select dbo.fn_ValidateIPv4( '127.0.0.258' );
*/
RETURN #Result
END;
I had to remove not de-supported built functions isnumeric etc...