So we have this SQL-query that we use in very many places that I would like to simplify by putting it in a function so that we don't have to write the query every single time. But when replacing the uses I stumbled upon an issue where we sometimes would use it inside an IF-statement.
Is there any way to use this as a function? Or maybe move it to a stored procedure instead?
Function:
ALTER FUNCTION [dbo].[fn_GetOption]
(
-- Add the parameters for the function here
#id int,
#searchKey nvarchar(32) = NULL
)
RETURNS nvarchar(128)
AS
BEGIN
DECLARE #Result nvarchar(128)
IF #searchKey IS NULL
BEGIN
SELECT #Result = [VALUE]
FROM [OPTIONS]
WHERE [ID] = #id
END
ELSE
BEGIN
SELECT #result = ISNULL(eoo.[VALUE], eo.[VALUE])
FROM
[OPTIONS] eo
LEFT OUTER JOIN [OPTIONS_OVERRIDE] eoo ON eo.[ID] = eoo.[ID] AND eoo.[SEARCH_KEY] = #searchKey
WHERE
eo.[ID] = #id
END
RETURN #Result
END
Usage: (not working)
IF 'Y' = EXEC [fn_GetOption] 69, 'myKey'
BEGIN
PRINT '1'
END
Remove the EXEC and add brackets:
IF 'Y' = dbo.[fn_GetOption] (69, 'myKey')
BEGIN
PRINT '1'
END
Related
I'm slowly learning more about PostgreSQL, as we are attempting to move to it from MSSQL Server.
In MSSQL I have the following code:
DECLARE ServiceabilityParameters
CURSOR FORWARD_ONLY READ_ONLY STATIC LOCAL FOR
SELECT WorkbookParameterType.ID,
WorkbookParameterType.Name,
WorkbookParameter.DefaultValue,
WorkbookParameter.CommandText
FROM WorkbookParameter
JOIN WorkbookParameterType ON WorkbookParameterType.ID = WorkbookParameter.WorkbookParameterTypeID
JOIN WorkbookParameterDirectionType ON WorkbookParameterDirectionType.ID = WorkbookParameter.WorkbookParameterDirectionTypeID
AND WorkbookParameterDirectionType.Writable = 1
WHERE WorkbookParameter.WorkbookID = #WorkbookID
OPEN ServiceabilityParameters
FETCH NEXT FROM ServiceabilityParameters INTO #WorkbookParameterTypeID, #WorkbookParameterTypeName, #WorkbookDefaultValue, #WorkbookCommandText
WHILE ##FETCH_STATUS = 0
BEGIN
DECLARE #ActualValue NVARCHAR(256) = NULL
IF #WorkbookCommandText IS NOT NULL
BEGIN
EXEC sp_executesql #statement = #WorkbookCommandText,
#params = N'#ApplicationContainerID INT, #Value NVARCHAR(256) OUTPUT',
#ApplicationContainerID = #ApplicationContainerID,
#Value = #ActualValue OUTPUT
END
IF #ActualValue IS NULL AND #WorkbookDefaultValue IS NOT NULL
BEGIN
SET #ActualValue = #WorkbookDefaultValue
END
INSERT #InputParameters (
ID, Name, Value
) VALUES (
#WorkbookParameterTypeID, #WorkbookParameterTypeName, #ActualValue
)
FETCH NEXT FROM ServiceabilityParameters INTO #WorkbookParameterTypeID, #WorkbookParameterTypeName, #WorkbookDefaultValue, #WorkbookCommandText
END
CLOSE ServiceabilityParameters
DEALLOCATE ServiceabilityParameters
I'm trying to work out how to do the sp_executesql part in a PostgreSQL function. I believe that I can do the rest, but most of the examples that I have found show a simple select with maybe a few variables, whereas I need to execute another function, with parameters, where the function name is text in a table.
Many Thanks.
In case you want to execute a function with parameters
EXECUTE 'SELECT Value FROM ' || v_workbookCommandText || '(ApplicationContainerID :=$1)'
INTO v_actualValue
USING v_applicationContainerID;
In case you need select records a function, you can using INOUT refcursor variable
EXECUTE 'SELECT Value FROM ' || v_workbookCommandText || '(ApplicationContainerID :=$1, refcur:= $2)'
INTO v_actualValue
USING v_applicationContainerID, my_cursor;
I think what you want to do is EXECUTE 'some string', like this:
EXECUTE 'SELECT count(*) FROM mytable WHERE inserted_by = $1 AND inserted <= $2'
INTO c
USING checked_user, checked_date;
Another option is to create and use your own PL/PGSQL functions.
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
In my procedure i am returning a int value.
ALTER PROCEDURE [dbo].[GetValue]
-- Add the parameters for the stored procedure here
#ID int,
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
DECLARE #isNew int
SET #isNew=0
DECLARE #returnedValue int
DECLARE #output int
SET #returnedValue=[dbo].fn_GetIsNewLecturer(#ID)
IF(#returnedValue=0)
BEGIN
PRINT 'new'
EXEC #output=[dbo].[GetNew] #ID
SELECT #output
END
ELSE
BEGIN
PRINT 'old'
EXEC #output=[dbo].[sp_GetOld] #ID
SELECT #output
END
RETURN #output
END
it return value should be int. But it returns Nullable int?. how to change it as int
Try this:
select [Output] = isnull(#output, 0)
Here's why it should work:
declare #i int
select ni = #i, nni = isnull(#i,0)
into #t
select is_nullable, *
from tempdb.sys.columns
where [object_id] = object_id(N'tempdb..#t')
drop table #t
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(''))
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