SQL nugget to turn a datetime2 into a NVARCHAR as 'YYYY-MM-DD HH:MM:SS.mmm'

DATETIME2_NVARCHAR_FORMATTER.sql

DECLARE @InsertDate DATETIME2 
SET @InsertDate = GETDATE()

DECLARE @InsertDateString NVARCHAR(24) 
SET @InsertDateString =
	CAST(YEAR(@InsertDate) AS NVARCHAR(4)) 
	+ '-'
	+ CASE 
		WHEN MONTH(@InsertDate) < 10 THEN '0'
		ELSE ''
	  END
	+ CAST(MONTH(@InsertDate) AS NVARCHAR(2)) 
	+ '-'
	+ CASE
		WHEN DAY(@InsertDate) < 10 THEN '0'
		ELSE ''
	  END
	+ CAST(DAY(@InsertDate) AS NVARCHAR(2))
	+ ' '
	+ CASE
		WHEN DATEPART(HOUR,@InsertDate) < 10 THEN '0'
		ELSE ''
	  END
	+ CAST(DATEPART(HOUR,@InsertDate) AS NVARCHAR(2))
	+ ':'
	+ CASE
		WHEN DATEPART(MINUTE,@InsertDate) < 10 THEN '0'
		ELSE ''
	  END
	+ CAST(DATEPART(MINUTE,@InsertDate) AS NVARCHAR(2))
	+ ':'
	+ CASE
		WHEN DATEPART(SECOND,@InsertDate) < 10 THEN '0'
		ELSE ''
	  END
	+ CAST(DATEPART(SECOND,@InsertDate) AS NVARCHAR(2))
	+ '.'
	+ CASE
		WHEN DATEPART(MILLISECOND,@InsertDate) < 10 THEN '00'
		WHEN DATEPART(MILLISECOND,@InsertDate) < 100 THEN '0'
		ELSE ''
	  END
	+ CAST(DATEPART(MILLISECOND,@InsertDate) AS NVARCHAR(3))