TSQL - how to execute a query as a variable? - tsql

DECLARE #query as varchar(200);
SET #query = 'SELECT COUNT(*) FROM table';
How can I execute #query, and additionally, is there way to store the query result directly when assigning the variable?

You can use sp_executesql with an output parameter to retrieve the scalar result.
DECLARE #query as nvarchar(200), #count int;
SET #query = N'SELECT #count = COUNT(*) FROM table';
EXEC sp_executesql #query,
N'#count int OUTPUT',
#count = #count OUTPUT
SELECT #count AS [#count]

You can do it like this:
exec (#query)
or, preferably, like this:
execute sp_executesql #query
For more info, check this MSDN article.

Try this :
declare #query as varchar(200)
select #query = COUNT(*) from table

Related

Combine query in the TSQL

I am trying to combine the SQL queries and getting the below error.
The name 'SELECT id,tbprojectnumber, importdatetime FROM [TestDatabase].[landing].[details]' is not a valid identifier.
DECLARE #Q1 varchar(5000)
SELECT #Q1 = 'SELECT id,tbprojectnumber, importdatetime'
DECLARE #Q3 varchar(5000)
SELECT #Q3 ='FROM [TestDatabase].[landing].[details]'
DECLARE #Q5 varchar(5000)
SELECT #Q5 = #Q1 +' '+#Q3
EXEC #Q5
when I am running query
SELECT id,tbprojectnumber, importdatetime
FROM [TestDatabase].[landing].[details]
I am able to get the results.
SET the variable value :
SET #Q5 = #Q1 +' '+#Q3
PRINT #Q5 -- Check before execution.
EXEC sp_executesql #Q5;
Use NVARCHAR() type while preparing dynamic queries.
For your sample data, you don't need to use two separate variable.

How to Get output from nested SP_executeSQL

Can you tell me how to insert executed variable #name in my table?
I had some coding and this is what i managed to do but I do not know whats next:
DECLARE #Name nvarchar(200);
DECLARE #dbcatalog nvarchar(128);
declare #sql nvarchar(4000)
select #name = N' select ID from ' + #DbCatalog + '.dbo.Table2 ';
SET #sql = 'insert into Table2(Name) values (#name)'
exec Sp_executeSQL #sql
Are you trying to copy ID values from one table into another? If so, then:
INSERT INTO Table2 (Name)
EXEC(#Name)

execute TSQL command with an output variable

I want to pass an SQL command to a variable and execute aggregate function for that. but when I run it,
this error is shown, and nothing appear for #cnt value ,
Must declare the variable '#cnt'
What's my mistake ?
DECLARE #ret varchar(300);
set #ret = '';
declare #cnt int;
set #ret = 'select #cnt = count(*) from TBL1'
EXEC (#ret)
print #cnt
You could use sp_executesql to access a variable inside of your dynamic SQL String:
DECLARE #SQLString nvarchar(500);
DECLARE #ParmDefinition nvarchar(500);
DECLARE #cnt varchar(30);
SET #SQLString = N'SELECT #cntOUT = count(1) from tbl1';
SET #ParmDefinition = N'#cntOUT varchar(30) OUTPUT';
EXECUTE sp_executesql #SQLString, #ParmDefinition, #cntOUT=#cnt OUTPUT;
SELECT #cnt;
The exec statement signals the end of a batch, so the print statement doesn't know about #cnt.
Try this instead:
DECLARE #ret varchar(300)
set #ret = ''
set #ret = 'declare #cnt int
select #cnt = count(*) from [Load].RINData
print #cnt'
EXEC (#ret)

How to get row count from EXEC() in a TSQL SPROC?

I have a TSQL sproc that builds a query as and executes it as follows:
EXEC (#sqlTop + #sqlBody + #sqlBottom)
#sqlTop contains something like SELECT TOP(x) col1, col2, col3...
TOP(x) will limit the rows returned, so later I want to know what the actual number of rows in the table is that match the query.
I then replace #sqlTop with something like:
EXEC ('SELECT #ActualNumberOfResults = COUNT(*) ' + #sqlBody)
I can see why this is not working, and why a value not declared error occurs, but I think it adequately describes what I'm trying to accomplish.
Any ideas?
use sp_executesql and an output parameter
example
DECLARE #sqlBody VARCHAR(500),#TableCount INT, #SQL NVARCHAR(1000)
SELECT #sqlBody = 'from sysobjects'
SELECT #SQL = N'SELECT #TableCount = COUNT(*) ' + #sqlBody
EXEC sp_executesql #SQL, N'#TableCount INT OUTPUT', #TableCount OUTPUT
SELECT #TableCount
GO
You could instead have the dynamic query return the result as a row set, which you would then insert into a table variable (could be a temporary or ordinary table as well) using the INSERT ... EXEC syntax. Afterwards you can just read the saved value into a variable using SELECT #var = ...:
DECLARE #rowcount TABLE (Value int);
INSERT INTO #rowcount
EXEC('SELECT COUNT(*) ' + #sqlBody);
SELECT #ActualNumberOfResults = Value FROM #rowcount;
Late in the day, but I found this method much simpler:
-- test setup
DECLARE #sqlBody nvarchar(max) = N'SELECT MyField FROM dbo.MyTable WHERE MyOtherField = ''x''';
DECLARE #ActualNumberOfResults int;
-- the goods
EXEC sp_executesql #sqlBody;
SET #ActualNumberOfResults = ##ROWCOUNT;
SELECT #ActualNumberOfResults;
After executing your actual query store the result of ##ROWCOUNT in any variable which you can use later.
EXEC sp_executesql 'SELECT TOP 10 FROM ABX'
SET #TotRecord = ##ROWCOUNT into your variable for later use.
Keep in mind that dynamic SQL has its own scope. Any variable declared/modified there will go out of scope after your EXEC or your sp_executesql.
Suggest writing to a temp table, which will be in scope to your dynamic SQL statement, and outside.
Perhaps put it in your sqlBottom:
CREATE TABLE ##tempCounter(MyNum int);
EXEC('SELECT #ActualNumberOfResults = COUNT(*) ' + #sqlBody +
'; INSERT INTO ##tempCounter(MyNum) VALUES(#ActualNumberOfResults);');
SELECT MyNum FROM ##tempCounter;
You can use output variable in SP_EXECUTESQL
DECLARE #SQL NVARCHAR(MAX);
DECLARE #ParamDefinition NVARCHAR(100) = '#ROW_SQL INT OUTPUT'
DECLARE #AFFECTED_ROWS INT;
SELECT
#SQL = N'SELECT 1 UNION ALL SELECT 2'
SELECT #SQL += 'SELECT #ROW_SQL = ##ROWCOUNT;';
EXEC SP_EXECUTESQL #SQL, #ParamDefinition, #ROW_SQL=#AFFECTED_ROWS OUTPUT;
PRINT 'Number of affected rows: ' + CAST(#AFFECTED_ROWS AS VARCHAR(20));
Ouput:
SQL2.sql: Number of affected rows: 2
Thanks Jesus Fernandez!
The only problem with the answers that create temporary tables (either using "DECLARE #rowcount TABLE" or "CREATE TABLE ##tempCounter(MyNum int)") is that you're having to read all the affected records off disk into memory. If you're expecting a large number of records this may take some time.
So if the answer is likely to be large the "use sp_executesql and an output parameter" solution is a more efficient answer. And it does appear to work.

How to get sp_executesql result into a variable?

I have a piece of dynamic SQL I need to execute, I then need to store the result into a variable.
I know I can use sp_executesql but can't find clear examples around about how to do this.
If you have OUTPUT parameters you can do
DECLARE #retval int
DECLARE #sSQL nvarchar(500);
DECLARE #ParmDefinition nvarchar(500);
DECLARE #tablename nvarchar(50)
SELECT #tablename = N'products'
SELECT #sSQL = N'SELECT #retvalOUT = MAX(ID) FROM ' + #tablename;
SET #ParmDefinition = N'#retvalOUT int OUTPUT';
EXEC sp_executesql #sSQL, #ParmDefinition, #retvalOUT=#retval OUTPUT;
SELECT #retval;
But if you don't, and can not modify the SP:
-- Assuming that your SP return 1 value
create table #temptable (ID int null)
insert into #temptable exec mysp 'Value1', 'Value2'
select * from #temptable
Not pretty, but works.
DECLARE #vi INT
DECLARE #vQuery NVARCHAR(1000)
SET #vQuery = N'SELECT #vi= COUNT(*) FROM <TableName>'
EXEC SP_EXECUTESQL
#Query = #vQuery
, #Params = N'#vi INT OUTPUT'
, #vi = #vi OUTPUT
SELECT #vi
DECLARE #tab AS TABLE (col1 VARCHAR(10), col2 varchar(10))
INSERT into #tab EXECUTE sp_executesql N'
SELECT 1 AS col1, 2 AS col2
UNION ALL
SELECT 1 AS col1, 2 AS col2
UNION ALL
SELECT 1 AS col1, 2 AS col2'
SELECT * FROM #tab
Return values are generally not used to "return" a result but to return success (0) or an error number (1-65K). The above all seem to indicate that sp_executesql does not return a value, which is not correct. sp_executesql will return 0 for success and any other number for failure.
In the below, #i will return 2727
DECLARE #s NVARCHAR(500)
DECLARE #i INT;
SET #s = 'USE [Blah]; UPDATE STATISTICS [dbo].[TableName] [NonExistantStatisticsName];';
EXEC #i = sys.sp_executesql #s
SELECT #i AS 'Blah'
SSMS will show this
Msg 2727, Level 11, State 1, Line 1
Cannot find index 'NonExistantStaticsName'.
If you want to return more than 1 value use this:
DECLARE #sqlstatement2 NVARCHAR(MAX);
DECLARE #retText NVARCHAR(MAX);
DECLARE #ParmDefinition NVARCHAR(MAX);
DECLARE #retIndex INT = 0;
SELECT #sqlstatement = 'SELECT #retIndexOUT=column1 #retTextOUT=column2 FROM XXX WHERE bla bla';
SET #ParmDefinition = N'#retIndexOUT INT OUTPUT, #retTextOUT NVARCHAR(MAX) OUTPUT';
exec sp_executesql #sqlstatement, #ParmDefinition, #retIndexOUT=#retIndex OUTPUT, #retTextOUT=#retText OUTPUT;
returned values are in #retIndex and #retText
Declare #variable int
Exec #variable = proc_name
DECLARE #ValueTable TABLE
(
Value VARCHAR (100)
)
SELECT #sql = N'SELECT SRS_SizeSetDetails.'+#COLUMN_NAME+' FROM SRS_SizeSetDetails WHERE FSizeID = '''+#FSizeID+''' AND SRS_SizeSetID = '''+#SRS_SizeSetID+'''';
INSERT INTO #ValueTable
EXEC sp_executesql #sql;
SET #Value='';
SET #Value = (SELECT TOP 1 Value FROM #ValueTable)
DELETE FROM #ValueTable
This worked for me:
DECLARE #SQL NVARCHAR(4000)
DECLARE #tbl Table (
Id int,
Account varchar(50),
Amount int
)
-- Lots of code to Create my dynamic sql statement
insert into #tbl EXEC sp_executesql #SQL
select * from #tbl
Here's something you can try
DECLARE #SqlStatement NVARCHAR(MAX) = ''
,#result XML
,#DatabaseName VARCHAR(100)
,#SchemaName VARCHAR(10)
,#ObjectName VARCHAR(200);
SELECT #DatabaseName = 'some database'
,#SchemaName = 'some schema'
,#ObjectName = 'some object (Table/View)'
SET #SqlStatement = '
SELECT #result = CONVERT(XML,
STUFF( ( SELECT *
FROM
(
SELECT TOP(100)
*
FROM ' + QUOTENAME(#DatabaseName) +'.'+ QUOTENAME(#SchemaName) +'.' + QUOTENAME(#ObjectName) + '
) AS A1
FOR XML PATH(''row''), ELEMENTS, ROOT(''recordset'')
), 1, 0, '''')
)
';
EXEC sp_executesql #SqlStatement,N'#result XML OUTPUT', #result = #result OUTPUT;
SELECT DISTINCT
QUOTENAME(r.value('fn:local-name(.)', 'VARCHAR(200)')) AS ColumnName
FROM #result.nodes('//recordset/*/*') AS records(r)
ORDER BY ColumnName
This was a long time ago, so not sure if this is still needed, but you could use ##ROWCOUNT variable to see how many rows were affected with the previous sql statement.
This is helpful when for example you construct a dynamic Update statement and run it with exec. ##ROWCOUNT would show how many rows were updated.
Here is the definition