SQL Server: Error message on dynamic procecure - sql

Question

I don't have much experience with dynamic procedures so the following was only an attempt.
The only part that is actually dynamic here is the table name which I tried to create by combining the fix part "MOC_" and the variable part #level.
Can someone tell me what I have to change here to make this work ?
The error I get when executing this points to the IF NOT EXISTS part:
Conversion failed when converting the nvarchar value 'IF NOT EXISTS (
SELECT *
FROM MOC_Nav2
WHERE itemID = ' to data type int.
My procedure:
ALTER PROCEDURE [dbo].[MOC_UpdateNav]
#level nvarchar(20),
#itemID int,
#parentID int,
#itemName nvarchar(100),
#sortID int,
#logStatus nvarchar(20),
#lastUpdate nvarchar(50),
#modBy varchar(50)
AS
BEGIN
SET NOCOUNT ON;
BEGIN
DECLARE #sql nvarchar(max)
SET #sql = 'IF NOT EXISTS
(
SELECT *
FROM MOC_' + #level + '
WHERE itemID = ' + #itemID + '
)
INSERT INTO MOC_' + #level + '
(
parentID,
itemName,
sortID,
logStatus,
lastUpdate,
modDate,
modBy
)
SELECT ' + #parentID + ',
' + #itemName + ',
' + #sortID + ',
' + #logStatus + ',
' + #lastUpdate + ',
GETDATE(),
' + #modBy + '
ELSE
UPDATE MOC_' + #level + '
SET parentID = ' + #parentID + ',
itemName = ' + #itemName + ',
sortID = ' + #sortID + ',
logStatus = ' + #logStatus + ',
lastUpdate = ' + #lastUpdate + ',
modDate = GETDATE(),
modBy = ' + #modBy + '
WHERE itemID = ' + #itemID + ''
EXEC(#sql)
END
END

Answer 1

#itemID is an int. Because it is used in the expression, everything else must be converted to a number, including your SQL text.
Convert #itemID (and other numbers) to nvarchar before concatenating it into the query:
SET #sql = N'IF NOT EXISTS
(
SELECT *
FROM MOC_' + #level + '
WHERE itemID = ' + cast(#itemID as nvarchar(30)) + ...