diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index a7abf8c2eee..c878a0ba4de 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -14604,7 +14604,7 @@ NULL baz</literallayout>(3 rows)</entry>
       <entry>No</entry>
       <entry>input arrays concatenated into array of one higher dimension
        (inputs must all have same dimensionality,
-        and cannot be empty or NULL)</entry>
+        and cannot be empty or null)</entry>
      </row>
 
      <row>
@@ -14628,7 +14628,7 @@ NULL baz</literallayout>(3 rows)</entry>
        otherwise the same as the argument data type
       </entry>
       <entry>Yes</entry>
-      <entry>the average (arithmetic mean) of all input values</entry>
+      <entry>the average (arithmetic mean) of all non-null input values</entry>
      </row>
 
      <row>
@@ -14756,7 +14756,7 @@ NULL baz</literallayout>(3 rows)</entry>
        <type>json</type>
       </entry>
       <entry>No</entry>
-      <entry>aggregates values as a JSON array</entry>
+      <entry>aggregates values, including nulls, as a JSON array</entry>
      </row>
 
      <row>
@@ -14773,7 +14773,7 @@ NULL baz</literallayout>(3 rows)</entry>
        <type>jsonb</type>
       </entry>
       <entry>No</entry>
-      <entry>aggregates values as a JSON array</entry>
+      <entry>aggregates values, including nulls, as a JSON array</entry>
      </row>
 
      <row>
@@ -14790,7 +14790,8 @@ NULL baz</literallayout>(3 rows)</entry>
        <type>json</type>
       </entry>
       <entry>No</entry>
-      <entry>aggregates name/value pairs as a JSON object</entry>
+      <entry>aggregates name/value pairs as a JSON object; values can be
+       null, but not names</entry>
      </row>
 
      <row>
@@ -14807,7 +14808,8 @@ NULL baz</literallayout>(3 rows)</entry>
        <type>jsonb</type>
       </entry>
       <entry>No</entry>
-      <entry>aggregates name/value pairs as a JSON object</entry>
+      <entry>aggregates name/value pairs as a JSON object; values can be
+       null, but not names</entry>
      </row>
 
      <row>
@@ -14823,7 +14825,7 @@ NULL baz</literallayout>(3 rows)</entry>
       <entry>Yes</entry>
       <entry>
        maximum value of <replaceable
-       class="parameter">expression</replaceable> across all input
+       class="parameter">expression</replaceable> across all non-null input
        values
       </entry>
      </row>
@@ -14841,7 +14843,7 @@ NULL baz</literallayout>(3 rows)</entry>
       <entry>Yes</entry>
       <entry>
        minimum value of <replaceable
-       class="parameter">expression</replaceable> across all input
+       class="parameter">expression</replaceable> across all non-null input
        values
       </entry>
      </row>
@@ -14863,7 +14865,7 @@ NULL baz</literallayout>(3 rows)</entry>
        same as argument types
       </entry>
       <entry>No</entry>
-      <entry>input values concatenated into a string, separated by delimiter</entry>
+      <entry>non-null input values concatenated into a string, separated by delimiter</entry>
      </row>
 
      <row>
@@ -14886,7 +14888,8 @@ NULL baz</literallayout>(3 rows)</entry>
        argument data type
       </entry>
       <entry>Yes</entry>
-      <entry>sum of <replaceable class="parameter">expression</replaceable> across all input values</entry>
+      <entry>sum of <replaceable class="parameter">expression</replaceable>
+       across all non-null input values</entry>
      </row>
 
      <row>
@@ -14903,7 +14906,8 @@ NULL baz</literallayout>(3 rows)</entry>
        <type>xml</type>
       </entry>
       <entry>No</entry>
-      <entry>concatenation of XML values (see also <xref linkend="functions-xml-xmlagg"/>)</entry>
+      <entry>concatenation of non-null XML values
+       (see also <xref linkend="functions-xml-xmlagg"/>)</entry>
      </row>
     </tbody>
    </tgroup>