diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..c98ee8f7ee 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -45,7 +45,7 @@ SELECT [ ALL | DISTINCT [ ON ( <replaceable class="parameter">expression</replac
     [ LIMIT { <replaceable class="parameter">count</replaceable> | ALL } ]
     [ OFFSET <replaceable class="parameter">start</replaceable> [ ROW | ROWS ] ]
     [ FETCH { FIRST | NEXT } [ <replaceable class="parameter">count</replaceable> ] { ROW | ROWS } { ONLY | WITH TIES } ]
-    [ FOR { UPDATE | NO KEY UPDATE | SHARE | KEY SHARE } [ OF <replaceable class="parameter">table_name</replaceable> [, ...] ] [ NOWAIT | SKIP LOCKED ] [...] ]
+    [ FOR { UPDATE | NO KEY UPDATE | SHARE | KEY SHARE } [ OF <replaceable class="parameter">from_reference</replaceable> [, ...] ] [ NOWAIT | SKIP LOCKED ] [...] ]
 
 <phrase>where <replaceable class="parameter">from_item</replaceable> can be one of:</phrase>
 
@@ -202,7 +202,11 @@ TABLE [ ONLY ] <replaceable class="parameter">table_name</replaceable> [ * ]
       is specified, the
       <command>SELECT</command> statement locks the selected rows
       against concurrent updates.  (See <xref linkend="sql-for-update-share"/>
-      below.)
+      below.)  <replaceable
+      class="parameter">from_reference</replaceable> must be a table
+      <replaceable class="parameter">alias</replaceable> or non-hidden
+      <replaceable class="parameter">table_name</replaceable> referenced
+      in the <literal>FROM</literal> clause.
      </para>
     </listitem>
    </orderedlist>