How to Set a variable using OPENQUERY in SQL Server - sql

Question

I am trying to read data from a table. This table have a list of table name.
for each row of the data set I want to run a couple of queries to pull data and insert it into a temporary table.
Here is What I have done
DECLARE #campName varchar(255);
DECLARE #sqlCommand varchar(1000);
DECLARE #sqlCommandMySQL varchar(1000);
DECLARE #LastRun varchar(60);
DECLARE #OPENQUERY varchar(1000);
DECLARE MY_CURSOR CURSOR
LOCAL STATIC READ_ONLY FORWARD_ONLY
FOR
SELECT LTRIM(RTRIM(CallListName)) AS CallListName
FROM [SMSQL1].[RDI_System].[dbo].[Campaigns]
WHERE dialer_campaign = 1 AND i3Server ='I3New' AND ClientID = 111 AND (EndDate IS NULL OR EndDate >= getdate() - 7)
OPEN MY_CURSOR
FETCH NEXT FROM MY_CURSOR INTO #campName
WHILE ##FETCH_STATUS = 0
BEGIN
--SET #LinkedServer = 'GUARDIAN';
SET #OPENQUERY = 'SELECT #LastRun = lr FROM OPENQUERY(GUARDIAN,''';
SET #sqlCommandMySQL = 'SELECT IFNULL(MAX(lastRun), DATE_SUB(NOW(), INTERVAL 7 DAY) ) AS lr
FROM guardian_dynamo.runtimes_i3
WHERE CampaignListName = "'+#campName+'" '')';
print #OPENQUERY + #sqlCommandMySQL;
EXEC(#OPENQUERY + #sqlCommandMySQL);
SET #sqlCommand = ' INSERT INTO #finalList(Attemtps, CAMPAIGNNAME, FINISHCODE, CALLDATE, AGENTID, RDINotes, PHONE, MERCHANTAccount)
SELECT ATTEMPTS, CAMPAIGNNAME, FINISHCODE, CALLDATE, AGENTID, RDINotes, PHONE, MERCHANTAccount
FROM [I3_IC4].[dbo].['+ #campName +']
WHERE CALLDATE > '''+#LastRun+''' AND ISNULL(status, ''C'') IN (''U'', ''E'', ''A'', ''F'') ';
EXEC (#sqlCommand);
FETCH NEXT FROM MY_CURSOR INTO #campName
END
CLOSE MY_CURSOR
DEALLOCATE MY_CURSOR;
every time I run this query I get this error
Msg 137, Level 15, State 1, Line 1
Must declare the scalar variable "#LastRun".
I am not sure why since I am declaring this variable on the top as you can see in my code above.
the took the output of print #OPENQUERY + #sqlCommandMySQL; and executed that manually. It worked with no issue and the variable #LastRun will have a datetime value as it should.

Answer 1

You need to use sp_executesql to execute the dynamic query which helps you output the variable(#LastRun)
Declare #OPENQUERY Nvarchar(max), #sqlCommandMySQL Nvarchar(max), #OPENQUERYFINAL Nvarchar(max)
....
SET #OPENQUERY = 'SELECT #LastRun = lr FROM OPENQUERY(GUARDIAN,''';
SET #sqlCommandMySQL = 'SELECT IFNULL(MAX(lastRun), DATE_SUB(NOW(), INTERVAL 7 DAY) ) AS lr
FROM guardian_dynamo.runtimes_i3
WHERE CampaignListName = "'+#campName+'" '')';
--print #OPENQUERY + #sqlCommandMySQL;
SET #OPENQUERYFINAL = #OPENQUERY + #sqlCommandMySQL;
EXEC sp_executesql #OPENQUERYFINAL,
N'#LastRun varchar(10) OUTPUT',
#LastRun output
Demo
DECLARE #str VARCHAR(10),
#sql NVARCHAR(max)
SET #sql= 'select #str=1 '
EXEC Sp_executesql
#sql,
N'#str varchar(10) OUTPUT',
#str output
PRINT #str