PQexec(), what should I do for the "NULL in command" problem?

Hello:

As you know the interface of PQexec():
PGresult *PQexec(PGconn *conn, const char *command);

"command" contains some SQL statements.

But there exist "\0" in some data filed, and I found PQexec() failed
on such situation.
Something like this:

PQexec(conn, "INSERT INTO tttt('ttttt', 'abc\0abc');

Does anyone know something about this?
How can I insert a record which has some NULLs in data filed?

Best Regards,
Jason