T-SQL Error Message 207 When passing values Dynamically - sql-server

Question

I am attempting to create a stored procedure that allows values to be passed to it, however, when I try to use Dynamic T-SQL I raise an error MSG 207
I know that the error message is supposed to indicate that the column name was misspelled in my statement thanks to the following site:
https://www.tsql.info/error/msg-207-level-16-invalid-column-name.php
This, however, does not make sense as the following hard coded statement works just fine.
INSERT INTO [dbo].[tDriversLicense] (DriversLicensePrefix, DriversLicenseSuffix, DateAdded, DriversLicenseNumber)
VALUES ('shockc', '11653798', GETDATE(), 'GAD4859');
ALTER PROCEDURE [dbo].[spAddDriversLicense]
-- Add the parameters for the stored procedure here
#DriversLicensePrefix NCHAR(8),
#DriversLicenseSuffix NCHAR(10)
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;
DECLARE #sqlInsertDriversLicense NVARCHAR(MAX)
SET #sqlInsertDriversLicense = 'INSERT INTO [dbo].[tDriversLicense] (DriversLicensePrefix, DriversLicenseSuffix, DateAdded, DriversLicenseNumber)
VALUES (' + #DriversLicensePrefix + ', ' + #DriversLicenseSuffix + ', GETDATE(), GPC4859);'
EXECUTE sp_executesql #sqlInsertDriversLicense
END
I've been spilling over this code for hours and I'm thoroughly confused as to why there is any difference between the two INSERT statements. The values being passed are the same but an error is raised when I attempt to pass them dynamically. How is this raising an error??
I've used some code from this video to attempt to learn how pass Scalar Values dynamically and have had luck in other stored procedures.
https://www.youtube.com/watch?v=RHHKG65WEoU

Answer 1

When working with dynamic strings, select them first, so you can check that the resulting syntax is workable.
You need single quotes in the result, so you need more than single, single quotes, in the code:
declare #DriversLicensePrefix nchar(8) = 'A2345678'
declare #DriversLicenseSuffix nchar(10) = 'abcdefghij'
DECLARE #sqlInsertDriversLicense nvarchar(max)
SET #sqlInsertDriversLicense = 'INSERT INTO [dbo].[tDriversLicense] (DriversLicensePrefix, DriversLicenseSuffix, DateAdded, DriversLicenseNumber)
VALUES (N''' + #DriversLicensePrefix + ''', N''' + #DriversLicenseSuffix + ''', ''' + convert(char(8),GETDATE(),112) + ''', ''GPC4859'');'
select #sqlInsertDriversLicense
+-------------------------------------------------------------------------------------------------------------------+
| result: |
+-------------------------------------------------------------------------------------------------------------------+
| INSERT INTO [dbo].[tDriversLicense] (DriversLicensePrefix, DriversLicenseSuffix, DateAdded, DriversLicenseNumber) |
| VALUES (N'A2345678', N'abcdefghij', '20181109', 'GPC4859'); |
+-------------------------------------------------------------------------------------------------------------------+
NB You should use convert(char(8),getdate(),112) SQL Server will recognize the YYYYMMDD format as a date value regardless of server default settings.
The result see above demonstrates what the insert statement MUST be, note that it it contains several single quotes.
When you are concatenating the SQL statement, you are also dealing with strings, and every part of that has to be contained within single quotes.
So there are multiple needs for single quotes.
And; So you need multiple single quotes throughout out the concatenation, some to help form the SQL statement, and others to be INSIDE that statement.
/* get this into #sql */
select 'Y' as col1;
declare #SQL as nvarchar(max)
set #SQL = N'select ''Y'' as col1;'
select #SQL;
+---------------------+
| #SQL |
+---------------------+
| select 'Y' as col1; |
+---------------------+
In the larger query 2 variables are defined a NCHAR(8) or (10) as you have defined them a Nchar then when inserting data into those you should prefix that input by N

Answer 2

As posted in a comment already there is no need for this dynamic approach at all.
The following code will show a straight and a dynamic approach. Try it out:
USE master;
GO
CREATE DATABASE testDB;
GO
USE testDB;
GO
CREATE TABLE TestTable(SomeContent VARCHAR(100),SomeDate DATETIME,SomeFixString VARCHAR(100));
GO
--This procedure will use the parameters directly. No need for any dynamic SQL:
CREATE PROCEDURE TestStraight(#content VARCHAR(100))
AS
BEGIN
INSERT INTO TestTable(SomeContent,SomeDate,SomeFixString)
VALUES(#content,GETDATE(),'Proc Straight');
END
GO
--this procedure will use real parameters. You should never use parameters in string concatenation. One day you might meet bobby tables...
CREATE PROCEDURE TestDynamic(#content VARCHAR(100))
AS
BEGIN
DECLARE #cmd NVARCHAR(MAX)=
N'INSERT INTO TestTable(SomeContent,SomeDate,SomeFixString)
VALUES(#DynamicContent,GETDATE(),''Proc Dynamic'');'
EXEC sp_executesql #cmd,N'#DynamicContent VARCHAR(100)',#DynamicContent=#content;
END
GO
--Test it
EXEC TestStraight 'yeah!';
EXEC TestDynamic 'oh yeah!';
SELECT * FROM TestTable;
GO
--Clean up
USE master;
GO
--careful with real data!
--DROP DATABASE testDB;