Character length or Byte Length

I encountered a small detail problem today and found it to be a long time.

String STR = "a.2104697aa (Wuhu jinaorui) B .2104697ba (Changsha Bosch )";

Str. Length = 40

In C #, the length of string STR is 40. Here it refers to the length of string.

If STR varchar (50) is inserted into the SQL database, the following error occurs: string or binary data wocould be truncated. If the string length is too long, it must be truncated.

Then, the result of the select Len ('A. 2104697aa (Wuhu jiangrui) B .2104697ba (Changsha Bosch) ') query is 40, which indicates that the length is not exceeded.

After searching, we found that the query result of select datalength ('A. 2379697aa (Wuhu jinaorui) B .2379697ba (Changsha Bosch) 'is 52.

Datalength: returns the length of the string in bytes.
Len: returns the length of characters.

The length of varchar refers to the length of the string in bytes.

Appendix: differences between varchar nvarchar char

From: http://www.cnblogs.com/yelaiju/archive/2010/05/29/1746826.html

Character length or Byte Length