I want to make a function that search in a table and returns rows that contain a certain word that I Insert like below. But when I use LIKE it give me an error: Incorrect syntax near '#perberesi'
CREATE FUNCTION perberesit7
(#perberesi varchar(100))
RETURNS #menu_rest TABLE
(emri_hotelit varchar(50),
emri_menuse varchar(50),
perberesit varchar(255))
AS
Begin
insert into #menu_rest
Select dbo.RESTORANTET.Emri_Rest, dbo.MENU.Emri_Pjatës, dbo.MENU.Pershkrimi
From RESTORANTET, MENU
Where dbo.MENU.Rest_ID=dbo.RESTORANTET.ID_Rest and
dbo.MENU.Pershkrimi LIKE %#perberesi%
return
End
Pleae help me...How can I use LIKE in this case
try using:
'%' + #perberesi + '%'
instead of:
%#perberesi%
Some Examples
Ok, I just realized that you are creating a function, which means that you can't use INSERT. You should also really take Gordon's advice and use explicit joins and table aliases.
CREATE FUNCTION perberesit7(#perberesi varchar(100))
RETURNS #menu_rest TABLE ( emri_hotelit varchar(50),
emri_menuse varchar(50),
perberesit varchar(255))
AS
Begin
return(
Select R.Emri_Rest, M.Emri_Pjatës, M.Pershkrimi
From RESTORANTET R
INNER JOIN MENU M
ON M.Rest_ID = R.ID_Rest
Where M.Pershkrimi LIKE '%' + #perberesi + '%')
End
Why do you have to define the return table?
The following is a inline table variable function that performs better than a multi-line table. I wrote one to return columns that have the two letters 'id'. Just modify for your own case.
See article from Wayne Sheffield.
http://blog.waynesheffield.com/wayne/archive/2012/02/comparing-inline-and-multistatement-table-valued-functions/
-- Use tempdb
use tempdb;
go
-- Simple ITVF
create function search_columns (#name varchar(128))
returns TABLE
return
(
select * from sys.columns where name like '%' + #name + '%'
)
go
-- Call the function
select * from search_columns('id');
go
However, since you have a '%' in the like clause at the front of the expression, a full table or index scan is likely. You might want to look at full text indexing if you data is large.
http://craftydba.com/?p=1629
Related
I have created the following Type:
CREATE TYPE dbo.expressions
AS TABLE
(
expression varchar(255)
);
GO
How can I, in a Stored Procedure, use the n types that I receive and do, with each one, an select with a like clause?
In terms of "programming" (and pseudo-code), would be something like this:
for each expression in expressions
rows+=select * from table where table.field LIKE '%' + expression[i] + '%'
I can always call the SP multiple times from my API but I was wondering if this is possible, and even faster, to do in SQL side.
You simply SELECT from / JOIN with an instance of the type. Assuming you have something like:
CREATE TYPE expressions AS TABLE (expression varchar(255));
CREATE PROCEDURE mysp(#expressions AS expressions) ...
You can use the variable like you would use a table:
SELECT *
FROM #expressions AS expressions
INNER JOIN yourtable ON yourtable.field LIKE '%' + expressions.expression + '%'
The above will allow you to use expression in select clause. Otherwise you can use the following:
SELECT *
FROM yourtable
WHERE EXISTS (
SELECT 1
FROM #expressions AS expressions
WHERE yourtable.field LIKE '%' + expressions.expression + '%'
)
How can I create a function like this?
function FN_something (#entrada char(50))
declare #consulta table
declare #notificacao varchar(50)
declare #multa float
declare #saida varchar(50)
set #consulta as = (select num_notificacao,num_multa from table where field = #entrada)
set #notificacao = #consulta.num_notificacao
set #multa = #consulta.num_multa
set #saida = "resultado: "+ #notificacao +";"+#multa
return #saida
Thanks in advance
I would not use a function... Scalar functions tend to be a real performance killer. Try to use something like this inline
SELECT 'resultado: '
+ ISNULL(CAST(t.num_notificacao AS VARCHAR(MAX)),'???')
+ ';'
+ ISNULL(CAST(t.num_multa AS VARCHAR(MAX)),'???')
FROM SomeTable AS t WHERE t.SomeField=#entrada;
If you need a function it was much better to use an inlined TVF (syntax without BEGIN...END and bind it into your query with CROSS APPLY.
Might be simplified:
If your columns are NOT NULL you can go without ISNULL()-function. If your columns are strings, you can do without CAST()... My code is defensive proramming :-D
Hint
If this is something you need more often, you might introduce a VIEW carrying this calculated column and use it instead of your table. You might include this value into your table as computed column as well...
UPDATE
Great, the VIEW you show in the comment is an inline TVF actually, which is very good!
My magic crystall ball tells me, that you might need something like this:
SELECT cl.*
,'resultado: ' + t.num_notificacao + ';' + t.num_multa AS CalculatedResult
FROM dbo.[CampoLivre876]('SomeParameter') AS cl
LEFT JOIN SomeOtherTable AS t ON cl.entrada=t.SomeField --should be only one related row per main row!
This will call the iTFV and join it to the other Table, where the two columns are living. I Assume, that the CampoLivre876-row knows its entrada key.
Hint 2:
If this works for you, you might include this approach directly into your existing iTVF.
UPDATE 2
You might try to change your function like here:
ALTER FUNCTION [dbo].[CampoLivre876] ()
RETURNS TABLE
RETURN
Select cl.mul_numero_notificacao + ';' + CAST(cl.mul_valor_multa as varchar(max)) AS ExistingColumn
,'resultado: ' + t.num_notificacao + ';' + CAST(t.num_multa AS varchar(max)) AS CalculatedResult
From Campo_Livre AS cl With(NoLock)
INNER JOIN SomeOtherTable AS t ON cl.entrada=t.SomeField;
This should read all lines in one go. Reading 1 row after the other is - in almost all cases - something really, really bad...
Here is an example of a function with correct SQL Server syntax:
create function FN_something (
#entrada char(50) -- should probably be `varchar(50)` rather than `char(50)`
) returns varchar(50)
begin
declare #saida varchar(50);
select #saida = 'resultado: ' + num_notificacao + ';' + num_multa
from table
where field = #entrada;
return #saida;
end;
Note: This assumes that the num_ columns are strings, not numbers. If they are numbers, you need to convert them or use concat().
EDIT:
A function really isn't appropriate for this. Probably the best solution is a computed column:
alter table t add something as (concat('resultado: ', num_notificacao, ';', num_multa);
Then you can get the value directly from the table. In earlier versions of SQL Server, you would use a view rather than computed column.
Given a table as below where fn contains the name of an existing table valued functions and param contains the param to be passed to the function
fn | param
----------------
'fn_one' | 1001
'fn_two' | 1001
'fn_one' | 1002
'fn_two' | 1002
Is there a way to get a resulting table like this by using set-based operations?
The resulting table would contain 0-* lines for each line from the first table.
param | resultval
---------------------------
1001 | 'fn_one_result_a'
1001 | 'fn_one_result_b'
1001 | 'fn_two_result_one'
1002 | 'fn_two_result_one'
I thought I could do something like (pseudo)
select t1.param, t2.resultval
from table1 t1
cross join exec sp_executesql('select * from '+t1.fn+'('+t1.param+')') t2
but that gives a syntax error at exec sp_executesql.
Currently we're using cursors to loop through the first table and insert into a second table with exec sp_executesql. While this does the job correctly, it is also the heaviest part of a frequently used stored procedure and I'm trying to optimize it. Changes to the data model would probably imply changes to most of the core of the application and that would cost more then just throwing hardware at sql server.
I believe that this should do what you need, using dynamic SQL to generate a single statement that can give you your results and then using that with EXEC to put them into your table. The FOR XML trick is a common one for concatenating VARCHAR values together from multiple rows. It has to be written with the AS [text()] for it to work.
--=========================================================
-- Set up
--=========================================================
CREATE TABLE dbo.TestTableFunctions (function_name VARCHAR(50) NOT NULL, parameter VARCHAR(20) NOT NULL)
INSERT INTO dbo.TestTableFunctions (function_name, parameter)
VALUES ('fn_one', '1001'), ('fn_two', '1001'), ('fn_one', '1002'), ('fn_two', '1002')
CREATE TABLE dbo.TestTableFunctionsResults (function_name VARCHAR(50) NOT NULL, parameter VARCHAR(20) NOT NULL, result VARCHAR(200) NOT NULL)
GO
CREATE FUNCTION dbo.fn_one
(
#parameter VARCHAR(20)
)
RETURNS TABLE
AS
RETURN
SELECT 'fn_one_' + #parameter AS result
GO
CREATE FUNCTION dbo.fn_two
(
#parameter VARCHAR(20)
)
RETURNS TABLE
AS
RETURN
SELECT 'fn_two_' + #parameter AS result
GO
--=========================================================
-- The important stuff
--=========================================================
DECLARE #sql VARCHAR(MAX)
SELECT #sql =
(
SELECT 'SELECT ''' + T1.function_name + ''', ''' + T1.parameter + ''', F.result FROM ' + T1.function_name + '(' + T1.parameter + ') F UNION ALL ' AS [text()]
FROM
TestTableFunctions T1
FOR XML PATH ('')
)
SELECT #sql = SUBSTRING(#sql, 1, LEN(#sql) - 10)
INSERT INTO dbo.TestTableFunctionsResults
EXEC(#sql)
SELECT * FROM dbo.TestTableFunctionsResults
--=========================================================
-- Clean up
--=========================================================
DROP TABLE dbo.TestTableFunctions
DROP TABLE dbo.TestTableFunctionsResults
DROP FUNCTION dbo.fn_one
DROP FUNCTION dbo.fn_two
GO
The first SELECT statement (ignoring the setup) builds a string which has the syntax to run all of the functions in your table, returning the results all UNIONed together. That makes it possible to run the string with EXEC, which means that you can then INSERT those results into your table.
A couple of quick notes though... First, the functions must all return identical result set structures - the same number of columns with the same data types (technically, they might be able to be different data types if SQL Server can always do implicit conversions on them, but it's really not worth the risk). Second, if someone were able to update your functions table they could use SQL injection to wreak havoc on your system. You'll need that to be tightly controlled and I wouldn't let users just enter in function names, etc.
You cannot access objects by referencing their names in a SQL statement. One method would be to use a case statement:
select t1.*,
(case when fn = 'fn_one' then dbo.fn_one(t1.param)
when fn = 'fn_two' then dbo.fn_two(t1.param)
end) as resultval
from table1 t1 ;
Interestingly, you could encapsulate the case as another function, and then do:
select t1.*, dbo.fn_generic(t1.fn, t1.param) as resultval
from table1 t1 ;
However, in SQL Server, you cannot use dynamic SQL in a user-defined function (defined in T-SQL), so you would still need to use case or similar logic.
Either of these methods is likely to be much faster than a cursor, because they do not require issuing multiple queries.
As far as I know, we can return a table as a result of a db function:
CREATE FUNCTION MyFunction(#Value varchar(100))
RETURNS table
AS RETURN (select * from MyTable where ColumnName = '#Value')
in this example we can make the column name as a parameter for the function. My question is, can we write the column name and table name as a parameter for the function? hence we can write a more generic function something like:
CREATE FUNCTION MyGenericSearchFunction(#TableName varchar(100), #ColumnName varchar(100), #Value varchar(100))
RETURNS table
AS RETURN (select * from #TableName where #ColumnName = '#Value')
No, you can't.
This would then be a dynamic query.
For dynamic queries in SQL Server, one has to use exec() or sp_executesql() functions, which are not allowed in functions.
I made the following function in SQL Server 2008 earlier this week that takes two parameters and uses them to select a column of "detail" records and returns them as a single varchar list of comma separated values. Now that I get to thinking about it, I would like to take this table and application-specific function and make it more generic.
I am not well-versed in defining SQL functions, as this is my first. How can I change this function to accept a single "column" worth of data, so that I can use it in a more generic way?
Instead of calling:
SELECT ejc_concatFormDetails(formuid, categoryName)
I would like to make it work like:
SELECT concatColumnValues(SELECT someColumn FROM SomeTable)
Here is my function definition:
FUNCTION [DNet].[ejc_concatFormDetails](#formuid AS int, #category as VARCHAR(75))
RETURNS VARCHAR(1000) AS
BEGIN
DECLARE #returnData VARCHAR(1000)
DECLARE #currentData VARCHAR(75)
DECLARE dataCursor CURSOR FAST_FORWARD FOR
SELECT data FROM DNet.ejc_FormDetails WHERE formuid = #formuid AND category = #category
SET #returnData = ''
OPEN dataCursor
FETCH NEXT FROM dataCursor INTO #currentData
WHILE (##FETCH_STATUS = 0)
BEGIN
SET #returnData = #returnData + ', ' + #currentData
FETCH NEXT FROM dataCursor INTO #currentData
END
CLOSE dataCursor
DEALLOCATE dataCursor
RETURN SUBSTRING(#returnData,3,1000)
END
As you can see, I am selecting the column data within my function and then looping over the results with a cursor to build my comma separated varchar.
How can I alter this to accept a single parameter that is a result set and then access that result set with a cursor?
Others have answered your main question - but let me point out another problem with your function - the terrible use of a CURSOR!
You can easily rewrite this function to use no cursor, no WHILE loop - nothing like that. It'll be tons faster, and a lot easier, too - much less code:
FUNCTION DNet.ejc_concatFormDetails
(#formuid AS int, #category as VARCHAR(75))
RETURNS VARCHAR(1000)
AS
RETURN
SUBSTRING(
(SELECT ', ' + data
FROM DNet.ejc_FormDetails
WHERE formuid = #formuid AND category = #category
FOR XML PATH('')
), 3, 1000)
The trick is to use the FOR XML PATH('') - this returns a concatenated list of your data columns and your fixed ', ' delimiters. Add a SUBSTRING() on that and you're done! As easy as that..... no dogged-slow CURSOR, no messie concatenation and all that gooey code - just one statement and that's all there is.
You can use table-valued parameters:
CREATE FUNCTION MyFunction(
#Data AS TABLE (
Column1 int,
Column2 nvarchar(50),
Column3 datetime
)
)
RETURNS NVARCHAR(MAX)
AS BEGIN
/* here you can do what you want */
END
You can use Table Valued Parameters as of SQL Server 2008, which would allow you to pass a TABLE variable in as a parameter. The limitations and examples for this are all in that linked article.
However, I'd also point out that using a cursor could well be painful for performance.
You don't need to use a cursor, as you can do it all in 1 SELECT statement:
SELECT #MyCSVString = COALESCE(#MyCSVString + ', ', '') + data
FROM DNet.ejc_FormDetails
WHERE formuid = #formuid AND category = #category
No need for a cursor
Your question is a bit unclear. In your first SQL statement it looks like you're trying to pass columns to the function, but there is no WHERE clause. In the second SQL statement you're passing a collection of rows (results from a SELECT). Can you supply some sample data and expected outcome?
Without fully understanding your goal, you could look into changing the parameter to be a table variable. Fill a table variable local to the calling code and pass that into the function. You could do that as a stored procedure though and wouldn't need a function.