I need to use | as a seperator in unix join command. i tried changing seperator using -t option but iit is not working. can u please help.

Try -t"|"

And next time post what you have tried and examples of the files.

I already used the same thing
join -t"|" fld1 fld2 file1 file2

sorry filename is long..is that right...
cant v escape "|"

Post the OS and version you are using. Post an example of the files content.

syntax is correct? If I try this on Solaris, it gives an error.

If this is suppose to be the error you are getting, it's not very clear (most OS's don't put "is that right". Post the actual error you are getting - don't add to it.
If it's complaining that the file name is too long, you could try to rename your file. Post the file name if this is the issue.

hey that one i said..it is not OS error...
I said i gave it as general file name coz file name is too long...
It is not showing any error msg..but files are not getting joined thats the problem.

Again, post the OS and version you are using. Post an example of the files content.