I'd like to pass a table as a parameter into a scaler UDF.
I'd also prefer to restrict the parameter to tables with only one column. (optional)
Is this possible?
EDIT
I don't want to pass a table name, I'd like to pass the table of data (as a reference I presume)
EDIT
I would want my Scaler UDF to basically take a table of values and return a CSV list of the rows.
IE
col1
"My First Value"
"My Second Value"
...
"My nth Value"
would return
"My First Value, My Second Value,... My nth Value"
I'd like to do some filtering on the table though, IE ensuring that there are no nulls and to ensure there are no duplicates. I was expecting something along the lines of:
SELECT dbo.MyFunction(SELECT DISTINCT myDate FROM myTable WHERE myDate IS NOT NULL)
This question is related to
sql
sql-server
sql-server-2005
parameters
user-defined-functions
I've been dealing with a very similar problem and have been able to achieve what I was looking for, even though I'm using SQL Server 2000. I know it is an old question, but think its valid to post here the solution since there should be others like me that use old versions and still need help.
Here's the trick: SQL Server won't accept passing a table to a UDF, nor you can pass a T-SQL query so the function creates a temp table or even calls a stored procedure to do that. So, instead, I've created a reserved table, which I called xtList. This will hold the list of values (1 column, as needed) to work with.
CREATE TABLE [dbo].[xtList](
[List] [varchar](1000) NULL
) ON [PRIMARY]
Then, a stored procedure to populate the list. This is not strictly necessary, but I think is very usefull and best practice.
-- =============================================
-- Author: Zark Khullah
-- Create date: 20/06/2014
-- =============================================
CREATE PROCEDURE [dbo].[xpCreateList]
@ListQuery varchar(2000)
AS
BEGIN
SET NOCOUNT ON;
DELETE FROM xtList
INSERT INTO xtList
EXEC(@ListQuery)
END
Now, just deal with the list in any way you want, using the xtList. You can use in a procedure (for executing several T-SQL commands), scalar functions (for retrieving several strings) or multi-statement table-valued functions (retrieves the strings but like it was inside a table, 1 string per row). For any of that, you'll need cursors:
DECLARE @Item varchar(100)
DECLARE cList CURSOR DYNAMIC
FOR (SELECT * FROM xtList WHERE List is not NULL)
OPEN cList
FETCH FIRST FROM cList INTO @Item
WHILE @@FETCH_STATUS = 0 BEGIN
<< desired action with values >>
FETCH NEXT FROM cList INTO @Item
END
CLOSE cList
DEALLOCATE cList
The desired action would be as follows, depending on which type of object created:
Stored procedures
-- =============================================
-- Author: Zark Khullah
-- Create date: 20/06/2014
-- =============================================
CREATE PROCEDURE [dbo].[xpProcreateExec]
(
@Cmd varchar(8000),
@ReplaceWith varchar(1000)
)
AS
BEGIN
DECLARE @Query varchar(8000)
<< cursor start >>
SET @Query = REPLACE(@Cmd,@ReplaceWith,@Item)
EXEC(@Query)
<< cursor end >>
END
/* EXAMPLES
(List A,B,C)
Query = 'SELECT x FROM table'
with EXEC xpProcreateExec(Query,'x') turns into
SELECT A FROM table
SELECT B FROM table
SELECT C FROM table
Cmd = 'EXEC procedure ''arg''' --whatchout for wrong quotes, since it executes as dynamic SQL
with EXEC xpProcreateExec(Cmd,'arg') turns into
EXEC procedure 'A'
EXEC procedure 'B'
EXEC procedure 'C'
*/
Scalar functions
-- =============================================
-- Author: Zark Khullah
-- Create date: 20/06/2014
-- =============================================
CREATE FUNCTION [dbo].[xfProcreateStr]
(
@OriginalText varchar(8000),
@ReplaceWith varchar(1000)
)
RETURNS varchar(8000)
AS
BEGIN
DECLARE @Result varchar(8000)
SET @Result = ''
<< cursor start >>
SET @Result = @Result + REPLACE(@OriginalText,@ReplaceWith,@Item) + char(13) + char(10)
<< cursor end >>
RETURN @Result
END
/* EXAMPLE
(List A,B,C)
Text = 'Access provided for user x'
with "SELECT dbo.xfProcreateStr(Text,'x')" turns into
'Access provided for user A
Access provided for user B
Access provided for user C'
*/
Multi-statement table-valued functions
-- =============================================
-- Author: Zark Khullah
-- Create date: 20/06/2014
-- =============================================
CREATE FUNCTION [dbo].[xfProcreateInRows]
(
@OriginalText varchar(8000),
@ReplaceWith varchar(1000)
)
RETURNS
@Texts TABLE
(
Text varchar(2000)
)
AS
BEGIN
<< cursor start >>
INSERT INTO @Texts VALUES(REPLACE(@OriginalText,@ReplaceWith,@Item))
<< cursor end >>
END
/* EXAMPLE
(List A,B,C)
Text = 'Access provided for user x'
with "SELECT * FROM dbo.xfProcreateInRow(Text,'x')" returns rows
'Access provided for user A'
'Access provided for user B'
'Access provided for user C'
*/
The following will enable you to quickly remove the duplicate,null values and return only the valid one as list.
CREATE TABLE DuplicateTable (Col1 INT)
INSERT INTO DuplicateTable
SELECT 8
UNION ALL
SELECT 1--duplicate
UNION ALL
SELECT 2 --duplicate
UNION ALL
SELECT 1
UNION ALL
SELECT 3
UNION ALL
SELECT 4
UNION ALL
SELECT 5
UNION
SELECT NULL
GO
WITH CTE (COl1,DuplicateCount)
AS
(
SELECT COl1,
ROW_NUMBER() OVER(PARTITION BY COl1 ORDER BY Col1) AS DuplicateCount
FROM DuplicateTable
WHERE (col1 IS NOT NULL)
)
SELECT COl1
FROM CTE
WHERE DuplicateCount =1
GO
CTE are valid in SQL 2005 , you could then store the values in a temp table and use it with your function.
Step 1: Create a Type as Table with name TableType that will accept a table having one varchar column
create type TableType
as table ([value] varchar(100) null)
Step 2: Create a function that will accept above declared TableType as Table-Valued Parameter and String Value as Separator
create function dbo.fn_get_string_with_delimeter (@table TableType readonly,@Separator varchar(5))
returns varchar(500)
As
begin
declare @return varchar(500)
set @return = stuff((select @Separator + value from @table for xml path('')),1,1,'')
return @return
end
Step 3: Pass table with one varchar column to the user-defined type TableType and ',' as separator in the function
select dbo.fn_get_string_with_delimeter(@tab, ',')
Cutting to the bottom line, you want a query like SELECT x FROM y to be passed into a function that returns the values as a comma separated string.
As has already been explained you can do this by creating a table type and passing a UDT into the function, but this needs a multi-line statement.
You can pass XML around without declaring a typed table, but this seems to need a xml variable which is still a multi-line statement i.e.
DECLARE @MyXML XML = (SELECT x FROM y FOR XML RAW);
SELECT Dbo.CreateCSV(@MyXml);
The "FOR XML RAW" makes the SQL give you it's result set as some xml.
But you can bypass the variable using Cast(... AS XML). Then it's just a matter of some XQuery and a little concatenation trick:
CREATE FUNCTION CreateCSV (@MyXML XML)
RETURNS VARCHAR(MAX)
BEGIN
DECLARE @listStr VARCHAR(MAX);
SELECT
@listStr =
COALESCE(@listStr+',' ,'') +
c.value('@Value[1]','nvarchar(max)')
FROM @myxml.nodes('/row') as T(c)
RETURN @listStr
END
GO
-- And you call it like this:
SELECT Dbo.CreateCSV(CAST(( SELECT x FROM y FOR XML RAW) AS XML));
-- Or a working example
SELECT Dbo.CreateCSV(CAST((
SELECT DISTINCT number AS Value
FROM master..spt_values
WHERE type = 'P'
AND number <= 20
FOR XML RAW) AS XML));
As long as you use FOR XML RAW all you need do is alias the column you want as Value, as this is hard coded in the function.
To obtain the column count on a table, use this:
select count(id) from syscolumns where id = object_id('tablename')
and to pass a table to a function, try XML as show here:
create function dbo.ReadXml (@xmlMatrix xml)
returns table
as
return
( select
t.value('./@Salary', 'integer') as Salary,
t.value('./@Age', 'integer') as Age
from @xmlMatrix.nodes('//row') x(t)
)
go
declare @source table
( Salary integer,
age tinyint
)
insert into @source
select 10000, 25 union all
select 15000, 27 union all
select 12000, 18 union all
select 15000, 36 union all
select 16000, 57 union all
select 17000, 44 union all
select 18000, 32 union all
select 19000, 56 union all
select 25000, 34 union all
select 7500, 29
--select * from @source
declare @functionArgument xml
select @functionArgument =
( select
Salary as [row/@Salary],
Age as [row/@Age]
from @source
for xml path('')
)
--select @functionArgument as [@functionArgument]
select * from readXml(@functionArgument)
/* -------- Sample Output: --------
Salary Age
----------- -----------
10000 25
15000 27
12000 18
15000 36
16000 57
17000 44
18000 32
19000 56
25000 34
7500 29
*/
Step 1:
CREATE TABLE [DBO].T_EMPLOYEES_DETAILS ( Id int, Name nvarchar(50), Gender nvarchar(10), Salary int )
Step 2:
CREATE TYPE EmpInsertType AS TABLE ( Id int, Name nvarchar(50), Gender nvarchar(10), Salary int )
Step 3:
/* Must add READONLY keyword at end of the variable */
CREATE PROC PRC_EmpInsertType @EmployeeInsertType EmpInsertType READONLY AS BEGIN INSERT INTO [DBO].T_EMPLOYEES_DETAILS SELECT * FROM @EmployeeInsertType END
Step 4:
DECLARE @EmployeeInsertType EmpInsertType
INSERT INTO @EmployeeInsertType VALUES(1,'John','Male',50000) INSERT INTO @EmployeeInsertType VALUES(2,'Praveen','Male',60000) INSERT INTO @EmployeeInsertType VALUES(3,'Chitra','Female',45000) INSERT INTO @EmployeeInsertType VALUES(4,'Mathy','Female',6600) INSERT INTO @EmployeeInsertType VALUES(5,'Sam','Male',50000)
EXEC PRC_EmpInsertType @EmployeeInsertType
=======================================
SELECT * FROM T_EMPLOYEES_DETAILS
OUTPUT
1 John Male 50000
2 Praveen Male 60000
3 Chitra Female 45000
4 Mathy Female 6600
5 Sam Male 50000
create table Project (ProjectId int, Description varchar(50));
insert into Project values (1, 'Chase tail, change directions');
insert into Project values (2, 'ping-pong ball in clothes dryer');
create table ProjectResource (ProjectId int, ResourceId int, Name varchar(15));
insert into ProjectResource values (1, 1, 'Adam');
insert into ProjectResource values (1, 2, 'Kerry');
insert into ProjectResource values (1, 3, 'Tom');
insert into ProjectResource values (2, 4, 'David');
insert into ProjectResource values (2, 5, 'Jeff');
SELECT *,
(SELECT Name + ' ' AS [text()]
FROM ProjectResource pr
WHERE pr.ProjectId = p.ProjectId
FOR XML PATH (''))
AS ResourceList
FROM Project p
-- ProjectId Description ResourceList
-- 1 Chase tail, change directions Adam Kerry Tom
-- 2 ping-pong ball in clothes dryer David Jeff
You can, however no any table. From documentation:
For Transact-SQL functions, all data types, including CLR user-defined types and user-defined table types, are allowed except the timestamp data type.
You can use user-defined table types.
Example of user-defined table type:
CREATE TYPE TableType
AS TABLE (LocationName VARCHAR(50))
GO
DECLARE @myTable TableType
INSERT INTO @myTable(LocationName) VALUES('aaa')
SELECT * FROM @myTable
So what you can do is to define your table type, for example TableType and define the function which takes the parameter of this type. An example function:
CREATE FUNCTION Example( @TableName TableType READONLY)
RETURNS VARCHAR(50)
AS
BEGIN
DECLARE @name VARCHAR(50)
SELECT TOP 1 @name = LocationName FROM @TableName
RETURN @name
END
The parameter has to be READONLY. And example usage:
DECLARE @myTable TableType
INSERT INTO @myTable(LocationName) VALUES('aaa')
SELECT * FROM @myTable
SELECT dbo.Example(@myTable)
Depending on what you want achieve you can modify this code.
EDIT: If you have a data in a table you may create a variable:
DECLARE @myTable TableType
And take data from your table to the variable
INSERT INTO @myTable(field_name)
SELECT field_name_2 FROM my_other_table
you can do something like this
/* CREATE USER DEFINED TABLE TYPE */
CREATE TYPE StateMaster AS TABLE
(
StateCode VARCHAR(2),
StateDescp VARCHAR(250)
)
GO
/*CREATE FUNCTION WHICH TAKES TABLE AS A PARAMETER */
CREATE FUNCTION TableValuedParameterExample(@TmpTable StateMaster READONLY)
RETURNS VARCHAR(250)
AS
BEGIN
DECLARE @StateDescp VARCHAR(250)
SELECT @StateDescp = StateDescp FROM @TmpTable
RETURN @StateDescp
END
GO
/*CREATE STORED PROCEDURE WHICH TAKES TABLE AS A PARAMETER */
CREATE PROCEDURE TableValuedParameterExample_SP
(
@TmpTable StateMaster READONLY
)
AS
BEGIN
INSERT INTO StateMst
SELECT * FROM @TmpTable
END
GO
BEGIN
/* DECLARE VARIABLE OF TABLE USER DEFINED TYPE */
DECLARE @MyTable StateMaster
/* INSERT DATA INTO TABLE TYPE */
INSERT INTO @MyTable VALUES('11','AndhraPradesh')
INSERT INTO @MyTable VALUES('12','Assam')
/* EXECUTE STORED PROCEDURE */
EXEC TableValuedParameterExample_SP @MyTable
GO
For more details check this link: http://sailajareddy-technical.blogspot.in/2012/09/passing-table-valued-parameter-to.html
Source: Stackoverflow.com