diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index ab252d9fc74..2dc3da88cf8 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -1210,9 +1210,10 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d
       When the <literal>\aset</literal> command is used, all combined SQL queries
       (separated by <literal>\;</literal>) have their columns stored into variables
       named after column names, and prefixed with <replaceable>prefix</replaceable>
-      if provided. If a query returns no row, no assignment is made and the variable
-      can be tested for existence to detect this. If a query returns more than one
-      row, the last value is kept.
+      if provided. If a query returns no rows, no assignment is made. You can detect
+      this by initializing the variable beforehand with a value that the query is
+      assumed never to return, and then checking whether it changes.
+      If a query returns more than one row, the last value is kept.
      </para>
 
      <para>