Context: SQL Server 2000
I've written a UDF that gives me the text between two other texts, viz
CREATE FUNCTION dbo.StrBetween
(
#Text nvarchar(4000),
#Lhs nvarchar(4000),
#Rhs nvarchar(4000)
)
RETURNS nvarchar(4000)
AS
BEGIN
DECLARE #LhsOffset INT;
DECLARE #RhsOffset INT;
DECLARE #Result NVARCHAR(4000);
SET #LhsOffset = CHARINDEX( #Lhs, #Text );
IF #LhsOffset = 0
BEGIN
RETURN #Text;
END
SET #Result = SUBSTRING( #Text, #LhsOffset+1, LEN(#Text)-LEN(#Lhs));
SET #RhsOffset = CHARINDEX( #Rhs, #Result );
IF #RhsOffset = 0
BEGIN
RETURN #Result;
END
SET #Result = SUBSTRING( #Result, 1, #RhsOffset - 1 );
RETURN #Result;
END
This works fine in SQL Query Analyser if I have, say,
SELECT dbo.StrBetween('dog','d','g')
However, when I pass a column in as the value of the first argument, I get no response. For example,
SELECT [TEST].[dbo].StrBetween(Referrer,'//', '/') as tst FROM tblTest
Referrer is declared as an nvarchar field. I'm a newbie when it comes to T-SQL. What obvious thing am I not seeing?
It's not an issue with calling - it's a logic issue, and the fact that your #Rhs value is part of the #Lhs value.
SET #Result = SUBSTRING( #Text, #LhsOffset+1, LEN(#Text)-LEN(#Lhs));
This is removing the first character of your #Lhs string. However, since the second character is /, and that's what your #Rhs match is searching for, it immediately finds it at position 1 and so you get an empty string.
Instead, try:
SET #Result = SUBSTRING( #Text, #LhsOffset+LEN(#Lhs), 4000);
You don't have to be exact with computing a length. If you ask for 4000 characters and the string is only 12 characters long, SUBSTRING will give you back at most 12 characters. So don't bother computing the new length.
Related
Let's say I have data:
heloo
cuube
triniity
How to write script that will replace those "doubled" characters with only one? So the result from the above data set would be:
helo
cube
trinity
Usually I post some script where I tried to achieve this, but this time I can't think of any.
This should work:
CREATE PROCEDURE remove_duplicate_characters(#string VARCHAR(100))
AS
DECLARE #result VARCHAR(100)
SET #result=''
SELECT #result=#result+MIN(SUBSTRING(#string ,number,1)) FROM
(
SELECT number FROM master..spt_values WHERE type='p' AND number BETWEEN 1 AND len(#string )) AS t GROUP BY SUBSTRING(#string,number,1) ORDER BY MIN(number)
)
SELECT #result
GO
You then call it like this:
EXEC remove_duplicate_characters 'heloo'
Source
This script does not depend on having access to master functions, and just relies on t-sql string functions.
declare #word varchar(100) = 'aaaacuuuuuubeeeee', #result varchar(100) = ''
declare #letter char, #idx int = 0, #lastletter char = ''
while(#idx <= len(#word))
begin
select #letter = substring(#word,#idx,1)
if (#letter != #lastletter)
begin
select #result = concat(#result,#letter)
end
select #lastletter = #letter,#idx = #idx + 1
end
select #result
my problem is pretty simple. I get a value from a sql select which looks like this:
ARAMAUBEBABRBGCNDKDEEEFOFIFRGEGRIEISITJPYUCAKZKG
and I need it like this:
AR,AM,AU,BE,BA,BR,BG,CN,DK,DE,EE,FO,FI,FR,GE,GR,IE,IS,IT,JP,YU,CA,KZ,KG
The length is different in each dataset.
I tried it with format(), stuff() and so on but nothing brought me the result I need.
Thanks in advance
With a little help of a numbers table and for xml path.
-- Sample table
declare #T table
(
Value nvarchar(100)
)
-- Sample data
insert into #T values
('ARAMAU'),
('ARAMAUBEBABRBGCNDKDEEEFOFIFRGEGRIEISITJPYUCAKZKG')
declare #Len int
set #Len = 2;
select stuff(T2.X.value('.', 'nvarchar(max)'), 1, 1, '')
from #T as T1
cross apply (select ','+substring(T1.Value, 1+Number*#Len, #Len)
from Numbers
where Number >= 0 and
Number < len(T1.Value) / #Len
order by Number
for xml path(''), type) as T2(X)
Try on SE-Data
Time to update your resume.
create function DontDoThis (
#string varchar(max),
#count int
)
returns varchar(max)
as
begin
declare #result varchar(max) = ''
declare #token varchar(max) = ''
while DATALENGTH(#string) > 0
begin
select #token = left(#string, #count)
select #string = REPLACE(#string, #token, '')
select #result += #token + case when DATALENGTH(#string) = 0 then '' else ',' end
end
return #result
end
Call:
declare #test varchar(max) = 'ARAMAUBEBABRBGCNDKDEEEFOFIFRGEGRIEISITJPYUCAKZKG'
select dbo.DontDoThis(#test, 2)
gbn's comment is exactly right, if not very diplomatic :) TSQL is a poor language for string manipulation, but if you write a CLR function to do this then you will have the best of both worlds: .NET string functions called from pure TSQL.
I believe this is what QQping is looking for.
-- select .dbo.DelineateEachNth('ARAMAUBEBABRBGCNDKDEEEFOFIFRGEGRIEISITJPYUCAKZKG',2,',')
create function DelineateEachNth
(
#str varchar(max), -- Incoming String to parse
#length int, -- Length of desired segment
#delimiter varchar(100) -- Segment delimiter (comma, tab, line-feed, etc)
)
returns varchar(max)
AS
begin
declare #resultString varchar(max) = ''
-- only set delimiter(s) when lenght of string is longer than desired segment
if LEN(#str) > #length
begin
-- continue as long as there is a remaining string to parse
while len(#str) > 0
begin
-- as long as know we still need to create a segment...
if LEN(#str) > #length
begin
-- build result string from leftmost segment length
set #resultString = #resultString + left(#str, #length) + #delimiter
-- continually shorten result string by current segment
set #str = right(#str, len(#str) - #length)
end
-- as soon as the remaining string is segment length or less,
-- just use the remainder and empty the string to close the loop
else
begin
set #resultString = #resultString + #str
set #str = ''
end
end
end
-- if string is less than segment length, just pass it through
else
begin
set #resultString = #str
end
return #resultString
end
With a little help from Regex
select Wow=
(select case when MatchIndex %2 = 0 and MatchIndex!=0 then ',' + match else match end
from dbo.RegExMatches('[^\n]','ARAMAUBEBABRBGCNDKDEEEFOFIFRGEGRIEISITJPYUCAKZKG',1)
for xml path(''))
DECLARE #str VARCHAR (MAX);
SELECT #str = COALESCE(#str + CHAR(10), '') +
'EXECUTE CreateDeno ' + CAST(ID AS VARCHAR)
FROM GL_To_Batch_Details
WHERE TYPE = 'C' AND
Deno_ID IS NULL;
--PRINT #str;--SELECT #str;
**EXEC(#str);**
EDITED
Does EXECUTE statement truncate strings to 8,000 chars like PRINT? How can I execute a dynamic SQL statement having more than 8,000 chars?
Any suggestion would be warmly appreciated.
PRINT is limited to 8k in output.
There is also an 8k limit in SSMS results pane.
Go to
tools -> options -> query results
to see the options.
To verify the length of the actual data, check:
SELECT LEN(#str)
When concatenating strings and the result is of type VARCHAR(MAX) and is over 8000 characters, at least one parameter and/or element being used in the concatenation need to be of the VARCHAR(MAX) type otherwise truncation will occur in the resultant string and will not be executable in an EXEC statement.
Example:
DECLARE #sql AS VARCHAR(MAX);
/* DECLARE #someItem AS VARCHAR(100); -- WILL CAUSE TRUNCATION WHEN #sql HAS LEN > 8000 */
DECLARE #someItem AS VARCHAR(MAX); -- All string variables need to be VARCHAR(MAX) when concatenating to another VARCHAR(MAX)
SET #someItem = 'Just assume the resulting #sql variable goes over 8000 characters...';
SET #sql = 'SELECT Something FROM Somewhere WHERE SomeField = ''' + #someItem + '''';
EXEC (#sql);
--PRINT #sql;
More information on MSDN.
"If the result of the concatenation of strings exceeds the limit of
8,000 bytes, the result is truncated. However, if at least one of the
strings concatenated is a large value type, truncation does not
occur."
The default length of a varchar is 30 characters:
CAST (ID AS VARCHAR)
Is it possible that id is longer than 30 characters?
The PRINT command is certainly limited to 8000 chars, irrespective of the length of the output (or whether it is varchar(max)). To work around this you need to output the string in chunks of <8000 chars
Update: In answer to your edit, exec doesn't limit the string length. I've put together the following example to show this:
DECLARE #str VARCHAR (MAX);
;WITH CTE_Count AS
(
select counter = 1
union all
select counter = counter+1
from CTE_Count
Where counter < 2000
)
SELECT
#str=COALESCE(#str + CHAR (10) ,
'' ) + 'select value=' + CAST (counter AS VARCHAR)
from
CTE_Count
Option (MAXRECURSION 0)
PRINT len(#str);--SELECT #str;
exec (#str)
Running this prints the length as 34892 chars, and all 2000 execute statements do run (be warned, it may take a few mins!)
It happens when you concatenate literals if one is not a varchar(max) the result ill be "implicit casted" to varchar(8000).
To generate a literal varchar(max) all parts must be varchar(max).
Note: It happened to me doing updates on varchar(max) columns, never tested with the EXEC command.
Also as noted in previous answers the print command holds a limit but you can try selecting that variable instead of printing it. (also ther's a limit on that select length you can configure on MS-SMS)
I also wanted to see what I was sending to Exec, and was confused by the PRINT limit. Had to write a proc to print in chunks.
CREATE PROCEDURE [dbo].[KFX_PrintVarcharMax]
#strMax varchar(max)
AS
BEGIN
SET NOCOUNT ON;
DECLARE
#index int = 0,
#start int = 1,
#blkSize int = 2000;
WHILE #Start < LEN(#strMax)
BEGIN
IF #start + #blkSize >= LEN(#strMax)
BEGIN
-- If remainder is less than blocksize print the remainder, and exit.
PRINT SUBSTRING(#strMax, #start, #blkSize)
BREAK;
END
-- Else find the next terminator (beyond the blksize)
SET #index = CHARINDEX(CHAR(10), #strMax, #start + #blkSize);
if #index >= #start
BEGIN
PRINT SubString(#strMax, #start, #index - #start + 1)
SET #start = #index + 1;
SET #blkSize = CASE WHEN #start + 2000 < LEN(#strMax) THEN 2000
ELSE LEN(#strMax) - #start + 1 END
END
ELSE
BEGIN
-- No char(10) found. Just print the rest.
PRINT SUBSTRING(#strMax, #start, LEN(#strMax))
BREAK;
END
END
END
I'm trying to write a UDF to translate a string that is either a guid or a project code associated with that guid into the guid:
CREATE FUNCTION fn_user_GetProjectID
(
#Project nvarchar(50)
)
RETURNS uniqueidentifier
AS
BEGIN
declare #ProjectID uniqueidentifier
BEGIN TRY
set #ProjectID = cast(#Project as uniqueidentifier)
END TRY
BEGIN CATCH
set #ProjectID = null
END CATCH
if(#ProjectID is null)
BEGIN
select #ProjectID = ProjectID from Project where projectcode = #Project
END
return #ProjectID
END
This works fine if the above code is embedded in my Stored Procedures, but I'd like to make a function out of it so that I follow DRY.
When I try to create the Function, I get errors like this:
Msg 443, Level 16, State 14, Procedure fn_user_GetProjectID, Line 16
Invalid use of side-effecting or time-dependent operator in 'BEGIN TRY' within a function.
Does anyone have an idea how I can get around this error?
Edit: I know I can't use Try-Catch in a Function, I guess a simplified questions would be, is there a way to do a cast that will just return NULL if the cast fails, instead of an error?
Apparently you can't use TRY-CATCH in a UDF.
According to this bug-reporting page for SQL Server:
Books Online documents this behaviour,
in topic "CREATE FUNCTION
(Transact-SQL)": "The following
statements are valid in a function:
[...] Control-of-Flow statements
except TRY...CATCH statements. [...]"
But they were giving hope for the future back in 2006:
However, this is a severe limitation
that should be removed in a future
release. You should post a suggestion
in this regard and I will
wholeheartedly vote for it.
From MSDN:
A column or local variable of
uniqueidentifier data type can be
initialized to a value in the
following ways:
By using the NEWID function.
By converting from a string constant
in the form
xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx,
in which each x is a hexadecimal digit
in the range 0-9 or a-f.
For example,
6F9619FF-8B86-D011-B42D-00C04FC964FF
is a valid uniqueidentifier value.
You can use pattern matching to verify the string. Note that this won't work for specific encoding that reduces the size of the GUID:
declare #Project nvarchar(50)
declare #ProjectID uniqueidentifier
declare #HexPattern nvarchar(268)
set #HexPattern =
'[A-F0-9][A-F0-9][A-F0-9][A-F0-9][A-F0-9][A-F0-9][A-F0-9][A-F0-9]' +
'[A-F0-9][A-F0-9][A-F0-9][A-F0-9][A-F0-9][A-F0-9][A-F0-9][A-F0-9]' +
'[A-F0-9][A-F0-9][A-F0-9][A-F0-9][A-F0-9][A-F0-9][A-F0-9][A-F0-9]' +
'[A-F0-9][A-F0-9][A-F0-9][A-F0-9][A-F0-9][A-F0-9][A-F0-9][A-F0-9]'
/* Take into account GUID can have curly-brackets or be missing dashes */
/* Note: this will not work for GUIDs that have been specially encoded */
set #Project = '{' + CAST(NEWID() AS VARCHAR(36)) + '}'
select #Project
set #Project = REPLACE(REPLACE(REPLACE(#Project,'{',''),'}',''),'-','')
/* Cast as uniqueid if pattern matches, otherwise return null */
if #Project LIKE #HexPattern
select #ProjectID = CAST(
SUBSTRING(#Project,1,8) + '-' +
SUBSTRING(#Project,9,4) + '-' +
SUBSTRING(#Project,13,4) + '-' +
SUBSTRING(#Project,17,4) + '-' +
SUBSTRING(#Project,21,LEN(#Project)-20)
AS uniqueidentifier)
select #ProjectID
I know I can't use Try-Catch in a Function, I guess a simplified questions would be, is there a way to do a cast that will just return NULL if the cast fails, instead of an error?
Starting from SQL Server 2012 you could use TRY_CAST/TRY_CONVERT functions:
Returns a value cast to the specified data type if the cast succeeds; otherwise, returns null.
CREATE FUNCTION fn_user_GetProjectID(#Project nvarchar(50))
RETURNS uniqueidentifier
AS
BEGIN
declare #ProjectID uniqueidentifier = TRY_CAST(#Project as uniqueidentifier);
IF(#ProjectID is null)
BEGIN
select #ProjectID = ProjectID from Project where projectcode = #Project;
END
return #ProjectID;
END
Not sure, but why not flip it around... at first glance I would simplify it like this:
select #ProjectID =
ISNULL((select ProjectID from Project where
projectcode = #Project)
,(cast #Project as uniqueidentifier))
If this doesn't provide enough error handling, I'm sure there's a better way to pre-check that the cast can work without using try/catch...
My brute force method was to create my own ToGuid() function that verifies it can be converted to a GUID first, if not, it returns null. It may not be very fast but it does the job, and it is probably faster to convert the guid if it is one than to try to look it up in the table. EDIT: I meant to give credit to this blog, where I got the basis of my code for this function: http://jesschadwick.blogspot.com/2007/11/safe-handling-of-uniqueidentifier-in.html
CREATE FUNCTION [dbo].[ToGuid]
(
#input NVARCHAR(MAX)
)
RETURNS uniqueidentifier
AS
BEGIN
DECLARE #isValidGuid BIT;
DECLARE #temp NVARCHAR(MAX);
SET #isValidGuid = 1;
SET #temp = UPPER(LTRIM(RTRIM(REPLACE(REPLACE(REPLACE(#input, '-', ''), '{', ''), '}', ''))));
IF(#temp IS NOT NULL AND LEN(#temp) = 32)
BEGIN
DECLARE #index INT;
SET #index = 1
WHILE (#index <= 32)
BEGIN
IF (SUBSTRING(#temp, #index, 1) IN ('0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', 'A', 'B', 'C', 'D', 'E', 'F'))
BEGIN
SET #index = #index + 1
END
ELSE
BEGIN
SET #isValidGuid = 0
BREAK;
END
END
END
ELSE
BEGIN
SET #isValidGuid = 0
END
DECLARE #ret UNIQUEIDENTIFIER
IF(#isValidGuid = 1)
set #ret = cast(#input AS UNIQUEIDENTIFIER)
ELSE
set #ret = NULL
RETURN #ret
END
I'm still very interested if there is a better answer than this.
Verify if #Project is a number using the ISNUMERIC function.
your code should looks like that:
declare #ProjectID uniqueidentifier
set #ProjectID = null
IF ISNUMERIC(#Project) > 0
BEGIN
set #ProjectID = cast(#Project as uniqueidentifier)
END
if(#ProjectID is null)
BEGIN
select #ProjectID = ProjectID from Project where projectcode = #Project
END
return #ProjectID
Basically I want to use PRINT statement inside a user defined function to aide my debugging.
However I'm getting the following error;
Invalid use of side-effecting or time-dependent operator in 'PRINT'
within a function.
Can this not be done?
Anyway to aid my user defined function debugging?
Tip:
generate error.
declare #Day int, #Config_Node varchar(50)
set #Config_Node = 'value to trace'
set #Day = #Config_Node
You will get this message:
Conversion failed when converting the varchar value 'value to trace'
to data type int.
No, sorry. User-defined functions in SQL Server are really limited, because of a requirement that they be deterministic. No way round it, as far as I know.
Have you tried debugging the SQL code with Visual Studio?
I got around this by temporarily rewriting my function to something like this:
IF OBJECT_ID ('[dbo].[fx_dosomething]', 'TF') IS NOT NULL
drop function [dbo].[fx_dosomething];
GO
create FUNCTION dbo.fx_dosomething ( #x numeric )
returns #t table (debug varchar(100), x2 numeric)
as
begin
declare #debug varchar(100)
set #debug = 'printme';
declare #x2 numeric
set #x2 = 0.123456;
insert into #t values (#debug, #x2)
return
end
go
select * from fx_dosomething(0.1)
I have tended in the past to work on my functions in two stages. The first stage would be to treat them as fairly normal SQL queries and make sure that I am getting the right results out of it. After I am confident that it is performing as desired, then I would convert it into a UDF.
Use extended procedure xp_cmdshell to run a shell command. I used it to print output to a file:
exec xp_cmdshell 'echo "mytextoutput" >> c:\debuginfo.txt'
This creates the file debuginfo.txt if it does not exist. Then it adds the text "mytextoutput" (without quotation marks) to the file. Any call to the function will write an additional line.
You may need to enable this db-server property first (default = disabled), which I realize may not be to the liking of dba's for production environments though.
No, you can not.
You can call a function from a stored procedure and debug a stored procedure (this will step into the function)
On my opinion, whenever I want to print or debug a function. I will copy the content of it to run as a normal SQL script. For example
My function:
create or alter function func_do_something_with_string(#input nvarchar(max)) returns nvarchar(max)
as begin
-- some function logic content
declare #result nvarchar(max)
set #result = substring(#input , 1, 10)
-- or do something else
return #result
end
Then I just copy and run this out of the function to debug
declare #input nvarchar(max) = 'Some string'
-- some function logic content
declare #result nvarchar(max)
set #result = substring(#input , 1, 10)
-- this line is added to check while debugging
print #result
-- or do something else
-- print the final result
print #result
You can try returning the variable you wish to inspect.
E.g. I have this function:
--Contencates seperate date and time strings and converts to a datetime. Date should be in format 25.03.2012. Time as 9:18:25.
ALTER FUNCTION [dbo].[ufn_GetDateTime] (#date nvarchar(11), #time nvarchar(11))
RETURNS datetime
AS
BEGIN
--select dbo.ufn_GetDateTime('25.03.2012.', '9:18:25')
declare #datetime datetime
declare #day_part nvarchar(3)
declare #month_part nvarchar(3)
declare #year_part nvarchar(5)
declare #point_ix int
set #point_ix = charindex('.', #date)
set #day_part = substring(#date, 0, #point_ix)
set #date = substring(#date, #point_ix, len(#date) - #point_ix)
set #point_ix = charindex('.', #date)
set #month_part = substring(#date, 0, #point_ix)
set #date = substring(#date, #point_ix, len(#date) - #point_ix)
set #point_ix = charindex('.', #date)
set #year_part = substring(#date, 0, #point_ix)
set #datetime = #month_part + #day_part + #year_part + ' ' + #time
return #datetime
END
When I run it.. I get:
Msg 241, Level 16, State 1, Line 1
Conversion failed when converting date and/or time from character string.
Arghh!!
So, what do I do?
ALTER FUNCTION [dbo].[ufn_GetDateTime] (#date nvarchar(11), #time nvarchar(11))
RETURNS nvarchar(22)
AS
BEGIN
--select dbo.ufn_GetDateTime('25.03.2012.', '9:18:25')
declare #day_part nvarchar(3)
declare #point_ix int
set #point_ix = charindex('.', #date)
set #day_part = substring(#date, 0, #point_ix)
return #day_part
END
And I get '25'. So, I am off by one and so I change to..
set #day_part = substring(#date, 0, #point_ix + 1)
Voila! Now it works :)