为什么在不指定长度的情况下将文本转换为varchar会将文本截断为30个字符？

I was searching an MS-SQL Server 2005 database to make sure that a certain text field was always a multiple of 8 in length. When I ran the following query, I got that several rows were of length 30. But when I investigated those records, I found that they were longer than that.I was searching an MS-SQL Server 2005 database