I am trying to select value from the system object,synonyms and then store into #variable. Then I can select data from #variable without caring the server.
However it keeps saying that I need to declare scalar variable. Can anyone help?
DECLARE #variable NVARCHAR(100)
SELECT #variable = name
FROM sys.synonyms
WHERE base_object_name = '[ABC].[dbo].[tblABC]'
SELECT * FROM #variable
Your query selects all names and successively stores them in the variable, meaning that each name overwrites the previously stored name, so only the last selected name is available in the variable when the SELECT statement terminates. If you want a variable that you can query like a temporary table, you will have to declare a table variable and insert the names into that "table", afterwards you can run a select statement against that variable:
Declare #variable table (name nvarchar(128));
INSERT INTO #variable (name)
SELECT name
FROM sys.synonyms
where base_object_name = '[ABC].[dbo].[tblABC]';
select * from #variable;
But: Also on this query, the server will "care".
The problem is that you need to return only one value to the variable. In this way:
Declare #variable nvarchar(100)
#variable = (SELECT TOP(1) name -- getting only one registry
FROM sys.synonyms where base_object_name =
'[ABC].[dbo].[tblABC]')
select #variable
You have to do next :
declare #names table ( name nvarchar(100 ) );
insert #names(name)
select name
FROM sys.synonyms
where base_object_name = '[ABC].[dbo].[tblABC]';
select * from #names
So how can I declare a temporary local variable with declare like:declare #tempVar varchar(max) within a user declared function?
The actual problem I'm trying to solve here is declaring and using variable within user defined stored function. I declare my function like this:
create function someFunction(#someParam varchar(100))
returns table
as
return (
declare #tempvar varchar(100)
set #tempvar = ''--Set the var to something useful
select * from sometable where somecolumn = (
select top 1 someColumn
from sometable
where somecolumn = #tempvar
)
)
Server complain about the variable being declared in wrong place. Where should I declare my variables in UDF like this?
You are creating an Inline Table-valued Function, this kind of functions must contain only a single SELECT statement.
If you want to use variables you must create a Multi-statement Table-valued Function. Your function would be declared as:
create function someFunction(#someParam varchar(100))
returns #table (field1 type, field2 type, ...)
as
begin
declare #tempvar varchar(100)
set #tempvar = ''--Set the var to something useful
insert #table
select * from sometable where somecolumn = (
select top 1 someColumn
from sometable
where somecolumn = #tempvar
)
return
end
If you wanted to keep the table function inline you could use a common table expression to define your variable(s) as shown below:
create function someFunction(#someParam varchar(100))
returns table
as
return (
WITH cte (tempvar) AS
(
SELECT '' -- Set the var to something useful
)
select * from sometable where somecolumn = (
select top 1 someColumn
from sometable
JOIN cte ON 1=1
where somecolumn = cte.tempvar
)
)
I have a Transact-SQL query that uses the IN operator. Something like this:
select * from myTable where myColumn in (1,2,3,4)
Is there a way to define a variable to hold the entire list "(1,2,3,4)"? How should I define it?
declare #myList {data type}
set #myList = (1,2,3,4)
select * from myTable where myColumn in #myList
DECLARE #MyList TABLE (Value INT)
INSERT INTO #MyList VALUES (1)
INSERT INTO #MyList VALUES (2)
INSERT INTO #MyList VALUES (3)
INSERT INTO #MyList VALUES (4)
SELECT *
FROM MyTable
WHERE MyColumn IN (SELECT Value FROM #MyList)
DECLARE #mylist TABLE (Id int)
INSERT INTO #mylist
SELECT id FROM (VALUES (1),(2),(3),(4),(5)) AS tbl(id)
SELECT * FROM Mytable WHERE theColumn IN (select id from #mylist)
There are two ways to tackle dynamic csv lists for TSQL queries:
1) Using an inner select
SELECT * FROM myTable WHERE myColumn in (SELECT id FROM myIdTable WHERE id > 10)
2) Using dynamically concatenated TSQL
DECLARE #sql varchar(max)
declare #list varchar(256)
select #list = '1,2,3'
SELECT #sql = 'SELECT * FROM myTable WHERE myColumn in (' + #list + ')'
exec sp_executeSQL #sql
3) A possible third option is table variables. If you have SQl Server 2005 you can use a table variable. If your on Sql Server 2008 you can even pass whole table variables in as a parameter to stored procedures and use it in a join or as a subselect in the IN clause.
DECLARE #list TABLE (Id INT)
INSERT INTO #list(Id)
SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4
SELECT
*
FROM
myTable
JOIN #list l ON myTable.myColumn = l.Id
SELECT
*
FROM
myTable
WHERE
myColumn IN (SELECT Id FROM #list)
Use a function like this:
CREATE function [dbo].[list_to_table] (#list varchar(4000))
returns #tab table (item varchar(100))
begin
if CHARINDEX(',',#list) = 0 or CHARINDEX(',',#list) is null
begin
insert into #tab (item) values (#list);
return;
end
declare #c_pos int;
declare #n_pos int;
declare #l_pos int;
set #c_pos = 0;
set #n_pos = CHARINDEX(',',#list,#c_pos);
while #n_pos > 0
begin
insert into #tab (item) values (SUBSTRING(#list,#c_pos+1,#n_pos - #c_pos-1));
set #c_pos = #n_pos;
set #l_pos = #n_pos;
set #n_pos = CHARINDEX(',',#list,#c_pos+1);
end;
insert into #tab (item) values (SUBSTRING(#list,#l_pos+1,4000));
return;
end;
Instead of using like, you make an inner join with the table returned by the function:
select * from table_1 where id in ('a','b','c')
becomes
select * from table_1 a inner join [dbo].[list_to_table] ('a,b,c') b on (a.id = b.item)
In an unindexed 1M record table the second version took about half the time...
I know this is old now but TSQL => 2016, you can use STRING_SPLIT:
DECLARE #InList varchar(255) = 'This;Is;My;List';
WITH InList (Item) AS (
SELECT value FROM STRING_SPLIT(#InList, ';')
)
SELECT *
FROM [Table]
WHERE [Item] IN (SELECT Tag FROM InList)
Starting with SQL2017 you can use STRING_SPLIT and do this:
declare #myList nvarchar(MAX)
set #myList = '1,2,3,4'
select * from myTable where myColumn in (select value from STRING_SPLIT(#myList,','))
DECLARE #myList TABLE (Id BIGINT) INSERT INTO #myList(Id) VALUES (1),(2),(3),(4);
select * from myTable where myColumn in(select Id from #myList)
Please note that for long list or production systems it's not recommended to use this way as it may be much more slower than simple INoperator like someColumnName in (1,2,3,4) (tested using 8000+ items list)
slight improvement on #LukeH, there is no need to repeat the "INSERT INTO":
and #realPT's answer - no need to have the SELECT:
DECLARE #MyList TABLE (Value INT)
INSERT INTO #MyList VALUES (1),(2),(3),(4)
SELECT * FROM MyTable
WHERE MyColumn IN (SELECT Value FROM #MyList)
No, there is no such type. But there are some choices:
Dynamically generated queries (sp_executesql)
Temporary tables
Table-type variables (closest thing that there is to a list)
Create an XML string and then convert it to a table with the XML functions (really awkward and roundabout, unless you have an XML to start with)
None of these are really elegant, but that's the best there is.
If you want to do this without using a second table, you can do a LIKE comparison with a CAST:
DECLARE #myList varchar(15)
SET #myList = ',1,2,3,4,'
SELECT *
FROM myTable
WHERE #myList LIKE '%,' + CAST(myColumn AS varchar(15)) + ',%'
If the field you're comparing is already a string then you won't need to CAST.
Surrounding both the column match and each unique value in commas will ensure an exact match. Otherwise, a value of 1 would be found in a list containing ',4,2,15,'
As no one mentioned it before, starting from Sql Server 2016 you can also use json arrays and OPENJSON (Transact-SQL):
declare #filter nvarchar(max) = '[1,2]'
select *
from dbo.Test as t
where
exists (select * from openjson(#filter) as tt where tt.[value] = t.id)
You can test it in
sql fiddle demo
You can also cover more complicated cases with json easier - see Search list of values and range in SQL using WHERE IN clause with SQL variable?
This one uses PATINDEX to match ids from a table to a non-digit delimited integer list.
-- Given a string #myList containing character delimited integers
-- (supports any non digit delimiter)
DECLARE #myList VARCHAR(MAX) = '1,2,3,4,42'
SELECT * FROM [MyTable]
WHERE
-- When the Id is at the leftmost position
-- (nothing to its left and anything to its right after a non digit char)
PATINDEX(CAST([Id] AS VARCHAR)+'[^0-9]%', #myList)>0
OR
-- When the Id is at the rightmost position
-- (anything to its left before a non digit char and nothing to its right)
PATINDEX('%[^0-9]'+CAST([Id] AS VARCHAR), #myList)>0
OR
-- When the Id is between two delimiters
-- (anything to its left and right after two non digit chars)
PATINDEX('%[^0-9]'+CAST([Id] AS VARCHAR)+'[^0-9]%', #myList)>0
OR
-- When the Id is equal to the list
-- (if there is only one Id in the list)
CAST([Id] AS VARCHAR)=#myList
Notes:
when casting as varchar and not specifying byte size in parentheses the default length is 30
% (wildcard) will match any string of zero or more characters
^ (wildcard) not to match
[^0-9] will match any non digit character
PATINDEX is an SQL standard function that returns the position of a pattern in a string
DECLARE #StatusList varchar(MAX);
SET #StatusList='1,2,3,4';
DECLARE #Status SYS_INTEGERS;
INSERT INTO #Status
SELECT Value
FROM dbo.SYS_SPLITTOINTEGERS_FN(#StatusList, ',');
SELECT Value From #Status;
Most of these seem to focus on separating-out each INT into its own parenthetical, for example:
(1),(2),(3), and so on...
That isn't always convenient. Especially since, many times, you already start with a comma-separated list, for example:
(1,2,3,...) and so on...
In these situations, you may care to do something more like this:
DECLARE #ListOfIds TABLE (DocumentId INT);
INSERT INTO #ListOfIds
SELECT Id FROM [dbo].[Document] WHERE Id IN (206,235,255,257,267,365)
SELECT * FROM #ListOfIds
I like this method because, more often than not, I am trying to work with IDs that should already exist in a table.
My experience with a commonly proposed technique offered here,
SELECT * FROM Mytable WHERE myColumn IN (select id from #mylist)
is that it induces a major performance degradation if the primary data table (Mytable) includes a very large number of records. Presumably, that is because the IN operator’s list-subquery is re-executed for every record in the data table.
I’m not seeing any offered solution here that provides the same functional result by avoiding the IN operator entirely. The general problem isn’t a need for a parameterized IN operation, it’s a need for a parameterized inclusion constraint. My favored technique for that is to implement it using an (inner) join:
DECLARE #myList varchar(50) /* BEWARE: if too small, no error, just missing data! */
SET #myList = '1,2,3,4'
SELECT *
FROM myTable
JOIN STRING_SPLIT(#myList,',') MyList_Tbl
ON myColumn = MyList_Tbl.Value
It is so much faster because the generation of the constraint-list table (MyList_Tbl) is executed only once for the entire query execution. Typically, for large data sets, this technique executes at least five times faster than the functionally equivalent parameterized IN operator solutions, like those offered here.
I think you'll have to declare a string and then execute that SQL string.
Have a look at sp_executeSQL