-- Prepare sample data
DECLARE	@TableA TABLE
		(
			Code CHAR(4) NOT NULL,
			Tests TINYINT NOT NULL
		)

INSERT	@TableA
	(
		Code,
		Tests
	)
SELECT	'0003', 1 UNION ALL
SELECT	'0005', 2 UNION ALL
SELECT	'0042', 1 UNION ALL
SELECT	'0913', 3

DECLARE	@TableB TABLE
		(
			Code CHAR(4) NOT NULL
		)

INSERT	@TableB
	(
		Code
	)
SELECT	'0003' UNION ALL
SELECT	'0005' UNION ALL
SELECT	'0042' UNION ALL
SELECT	'0913'

-- Display initial state of TableB
SELECT	*
FROM	@TableB

-- Do the work
INSERT	@TableB
	(
		Code
	)
SELECT	Code
FROM	(
		SELECT		a.Code,
				v.Number
		FROM		@TableA AS a
		INNER JOIN	master.dbo.spt_values AS v ON v.type = 'P'
		WHERE		v.Number BETWEEN 1 AND a.Tests

		EXCEPT

		SELECT	Code,
			ROW_NUMBER() OVER (PARTITION BY Code ORDER BY Code) AS Number
		FROM	@TableB
	) AS d

-- Display current state of TableB
SELECT	*
FROM	@TableB