How to insert varchar variable in dynamic sql query - sql

Question

I have a query with a select statement in a loop and at the same time I want to insert a varchar variable and selected value into a temporary table, but I get an error like:
Msg 207, Level 16, State 1, Line 2
Invalid column name 'SP419001_SID'
This SP419001_SID is the value contained in the varchar variable #dbName.
This is my query:
CREATE TABLE #tempCounter
(
dbName1 varchar(max),
counterNumber1 int
)
DECLARE
#counter INT = 1,
#max INT = 0,
#dbName VARCHAR(100),
#count INT = 0,
#SQLTEXT VARCHAR(MAX),
#counterNumber VARCHAR(10)
SELECT #max = COUNT(id) FROM #tempPnamePadd
WHILE #counter <= #max
BEGIN
SET #dbName='';
-- Do whatever you want with each row in your table variable filtering by the Id column
SELECT #dbName = name
FROM #tempPnamePadd
WHERE Id = #counter
PRINT #dbName
SET #SQLTEXT =
--SELECT distinct PN.NAME_FORMAT_CODE, NAME_BUSINESS, INDIVIDUAL_FIRST, A.ADDRESS_ID, A.ADDR_LINE_1, A.ADDR_LINE_2, A.ADDR_LINE_3, A.CITY, A.STATE
'DECLARE #dbn VARCHAR(200)
SET #dbn ='+ #dbName +';
INSERT INTO #tempCounter
(dbname1, counternumber1)
SELECT #dbn ,
(SELECT count(*)
FROM '+ #dbName +'.dbo.PRELA PR
INNER JOIN '+ #dbName +'.dbo.PNAME PN
ON PR.NAME_ID = PN.NAME_ID
INNER JOIN '+ #dbName +'.dbo.PNALK NK
ON PN.NAME_ID = NK.NAME_ID
INNER JOIN '+ #dbName +'.dbo.PADDR A
ON NK.ADDRESS_ID = A.ADDRESS_ID
WHERE (NAME_FORMAT_CODE=''B'' and NAME_BUSINESS like ''%BN'') OR
(NAME_FORMAT_CODE <> ''B'' and INDIVIDUAL_FIRST = ''John'') OR
(ADDR_LINE_1=''WELLS STREET'' AND CITY=''HOLLYWOOD'' AND STATE=''IA'')
)
'
--PRINT #SQLTEXT
EXEC (#SQLTEXT)
SET #counter = #counter + 1
END

Answer 1

This is very likely not the most efficient way to do this; most likely you should be using STRING_AGG or FOR XML PATH and STUFF to do this.
Anyway, you need to parametrise your variable, and quote your dynamic objects. This results in the below:
CREATE TABLE #tempCounter (dbName1 sysname,
counterNumber1 int);
DECLARE #counter int = 1,
#max int = 0,
#dbName sysname,
#count int = 0,
#SQLTEXT nvarchar(MAX),
#counterNumber varchar(10);
SELECT #max = COUNT(id)
FROM #tempPnamePadd;
WHILE #counter <= #max
BEGIN
SET #dbName = '';
-- Do whatever you want with each row in your table variable filtering by the Id column
SELECT #dbName = name
FROM #tempPnamePadd
WHERE Id = #counter;
PRINT #dbName;
SET #SQLTEXT = N'INSERT INTO #tempCounter
(dbname1, counternumber1)
SELECT #dbn ,
(SELECT count(*)
FROM ' + QUOTENAME(#dbName) + N'.dbo.PRELA PR
INNER JOIN ' + QUOTENAME(#dbName) + N'.dbo.PNAME PN
ON PR.NAME_ID = PN.NAME_ID
INNER JOIN ' + QUOTENAME(#dbName) + N'.dbo.PNALK NK
ON PN.NAME_ID = NK.NAME_ID
INNER JOIN ' + QUOTENAME(#dbName) + N'.dbo.PADDR A
ON NK.ADDRESS_ID = A.ADDRESS_ID
WHERE (NAME_FORMAT_CODE=''B'' and NAME_BUSINESS like ''%BN'') OR
(NAME_FORMAT_CODE <> ''B'' and INDIVIDUAL_FIRST = ''John'') OR
(ADDR_LINE_1=''WELLS STREET'' AND CITY=''HOLLYWOOD'' AND STATE=''IA'')
)
';
--PRINT #SQLTEXT
EXEC sp_executesql #SQLTEXT, N'#dbn sysname', #dbn = #dbName;
SET #counter = #counter + 1;
END;
Note I have also changed some of your data types.

Answer 2

You did not quote around #dbName in your dynamic query.
So instead of
SET #dbn ='SP419001_SID';
you get
SET #dbn =SP419001_SID;
Do
'DECLARE #dbn VARCHAR(200)
SET #dbn ='''+ #dbName +''';
INSERT INTO #tempCounter
...'