Generate a unique alphanumeric password using SQL

DECLARE @PwdLen SMALLINT,
@Chr TINYINT,
@Password VARCHAR(20)

-- Seed
SET @Chr = RAND(DATEPART(ms, GETDATE())) * 0
SET @Password = ''

SET @PwdLen = 1
WHILE @PwdLen < 8
BEGIN
SET @Chr = RAND() * 62
SET @Password = @Password + CHAR(
CASE WHEN @Chr < 10 THEN @Chr + 48 
WHEN @Chr BETWEEN 10 AND 35 THEN @Chr + 55 
ELSE @Chr + 61 
END)

SET @PwdLen = @PwdLen + 1
END

SELECT @Password [Password]