diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
new file mode 100644
index be92e6a..ddfb29a
*** a/doc/src/sgml/func.sgml
--- b/doc/src/sgml/func.sgml
***************
*** 364,371 ****
      </indexterm>
      Ordinary comparison operators yield null (signifying <quote>unknown</>),
      not true or false, when either input is null.  For example,
!     <literal>7 = NULL</> yields null.  When this behavior is not suitable,
!     use the
      <literal>IS <optional> NOT </> DISTINCT FROM</literal> constructs:
  <synopsis>
  <replaceable>expression</replaceable> IS DISTINCT FROM <replaceable>expression</replaceable>
--- 364,371 ----
      </indexterm>
      Ordinary comparison operators yield null (signifying <quote>unknown</>),
      not true or false, when either input is null.  For example,
!     <literal>7 = NULL</> yields null, as does <literal>7 &lt;&gt; NULL</>.  When
!     this behavior is not suitable, use the
      <literal>IS <optional> NOT </> DISTINCT FROM</literal> constructs:
  <synopsis>
  <replaceable>expression</replaceable> IS DISTINCT FROM <replaceable>expression</replaceable>