把int的变量拼接成字符串出错

比如输入两个int变量2013和3，然后输出2013-3-1

但是目前出错

ALTER PROCEDURE CountOrderRORInMonth
    @OrderId varchar(100) = null,
    @year int = null,
    @month int =null
AS
BEGIN
    PRINT '@OrderId is:'+CONVERT(varchar, @OrderId);
    PRINT '@year is:'+CONVERT(varchar, @year);
    PRINT '@month is:'+CONVERT(varchar, @month);
    Set DateFormat YMD;
    DECLARE @temp varchar,@beginROR datetime,@endROR datetime;
    SELECT @temp=(CONVERT(varchar, @year)+'-' + CONVERT(varchar, @month) +'-1');
    PRINT '@temp is:'+CONVERT(varchar, @temp);
    --SELECT @beginROR=@temp;
    --SET @beginROR=CAST(@temp AS datetime);
    --PRINT '@beginROR is:'+CONVERT(varchar, @beginROR);
END

输出的结果为啥是
EXEC CountOrderRORInMonth @OrderId='2013022048265668',@year=2013,@month=3;
GO
Warning: [FreeTDS][SQL Server]@OrderId is:2013022048265668
[FreeTDS][SQL Server]@year is:2013
[FreeTDS][SQL Server]@month is:3
[FreeTDS][SQL Server]@temp is:2

为2呢？奇怪

如果直接

SELECT CONVERT(varchar, 2013)+'-' + CONVERT(varchar, 3) +'-1'

得到
+----------+
| |
+----------+
| 2013-3-1 |
+----------+
1 rows in set (0.06 sec)

比较疑惑，存储过程为什么不能得到正确内容

[解决办法]
习惯不好

DECLARE @temp varchar
---》
DECLARE @temp varchar(20)
[解决办法]
转换可以不规定长度，定义一定要规定长度