diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 0417f2a2f65..6d7c2afe8fc 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -12467,7 +12467,7 @@ NULL baz</literallayout>(3 rows)</entry>
       </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>
@@ -12490,7 +12490,7 @@ NULL baz</literallayout>(3 rows)</entry>
        <type>double precision</type> for a floating-point argument,
        otherwise the same as the argument data type
       </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>
@@ -12610,7 +12610,7 @@ NULL baz</literallayout>(3 rows)</entry>
       <entry>
        <type>json</type>
       </entry>
-      <entry>aggregates values as a JSON array</entry>
+      <entry>aggregates values, including nulls, as a JSON array</entry>
      </row>
 
      <row>
@@ -12626,7 +12626,7 @@ NULL baz</literallayout>(3 rows)</entry>
       <entry>
        <type>jsonb</type>
       </entry>
-      <entry>aggregates values as a JSON array</entry>
+      <entry>aggregates values, including nulls, as a JSON array</entry>
      </row>
 
      <row>
@@ -12642,7 +12642,8 @@ NULL baz</literallayout>(3 rows)</entry>
       <entry>
        <type>json</type>
       </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>
@@ -12658,7 +12659,8 @@ NULL baz</literallayout>(3 rows)</entry>
       <entry>
        <type>jsonb</type>
       </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>
@@ -12673,7 +12675,7 @@ NULL baz</literallayout>(3 rows)</entry>
       <entry>same as argument type</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>
@@ -12690,7 +12692,7 @@ NULL baz</literallayout>(3 rows)</entry>
       <entry>same as argument type</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>
@@ -12711,7 +12713,7 @@ NULL baz</literallayout>(3 rows)</entry>
       <entry>
        same as argument types
       </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>
@@ -12733,7 +12735,8 @@ NULL baz</literallayout>(3 rows)</entry>
        <type>bigint</type> arguments, otherwise the same as the
        argument data type
       </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>
@@ -12749,7 +12752,8 @@ NULL baz</literallayout>(3 rows)</entry>
       <entry>
        <type>xml</type>
       </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>