diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f3cd3eb4045..c9478e7f0b1 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -13371,7 +13371,7 @@ 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>
@@ -13395,7 +13395,7 @@ 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>
@@ -13523,7 +13523,7 @@ 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>
@@ -13540,7 +13540,7 @@ 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>
@@ -13557,7 +13557,8 @@ 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>
@@ -13574,7 +13575,8 @@ 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>
@@ -13590,7 +13592,7 @@ 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>
@@ -13608,7 +13610,7 @@ 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>
@@ -13630,7 +13632,7 @@ 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>
@@ -13653,7 +13655,8 @@ 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>
@@ -13670,7 +13673,8 @@ 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>