diff --git a/doc/src/sgml/libpq.sgml b/doc/src/sgml/libpq.sgml
index 7f01fcc148..de9a0652a1 100644
--- a/doc/src/sgml/libpq.sgml
+++ b/doc/src/sgml/libpq.sgml
@@ -2488,9 +2488,14 @@ PGresult *PQexec(PGconn *conn, const char *command);
for more details about how the server handles multi-query strings.)
Note however that the returned
PGresult structure describes only the result
- of the last command executed from the string. Should one of the
- commands fail, processing of the string stops with it and the returned
- PGresult describes the error condition.
+ of the last command executed from the string.
+ If the strings contains COPY commands, the result of the
+ first of those is returned and further results should be fetched with
+ PQgetResult.
+ If the string contains only empty commands, an empty result is returned.
+ Otherwise, the result of the last non-empty command is returned.
+ Should one of the commands fail, processing of the string stops with it and
+ the returned PGresult describes the error condition.