<variablelist>
   <varlistentry id="plpgsql-quote-tips-1-quot">
    <term>1 quotation mark</term>
    <listitem>
     <para>
      To begin and end the function body, for example:
<programlisting>
CREATE FUNCTION foo() RETURNS integer AS '
          ....
' LANGUAGE plpgsql;
</programlisting>
      Anywhere within a single-quoted function body, quote marks
      <emphasis>must</emphasis> appear in pairs.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry id="plpgsql-quote-tips-2-quot">
    <term>2 quotation marks</term>
    <listitem>
     <para>
      For string literals inside the function body, for example:
<programlisting>
a_output := ''Blah'';
SELECT * FROM users WHERE f_name=''foobar'';
</programlisting>
      In the dollar-quoting approach, you'd just write:
<programlisting>
a_output := 'Blah';
SELECT * FROM users WHERE f_name='foobar';
</programlisting>
      which is exactly what the <application>PL/pgSQL</application> parser would see
      in either case.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry id="plpgsql-quote-tips-4-quot">
    <term>4 quotation marks</term>
    <listitem>
     <para>
      When you need a single quotation mark in a string constant inside the
      function body, for example:
<programlisting>
a_output := a_output || '' AND name LIKE ''''foobar'''' AND xyz''
</programlisting>
      The value actually appended to <literal>a_output</literal> would be:
      <literal> AND name LIKE 'foobar' AND xyz</literal>.
     </para>
     <para>
      In the dollar-quoting approach, you'd write:
<programlisting>
a_output := a_output || $$ AND name LIKE 'foobar' AND xyz$$
</programlisting>
      being careful that any dollar-quote delimiters around this are not
      just <literal>$$</literal>.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry id="plpgsql-quote-tips-6-quot">
    <term>6 quotation marks</term>
    <listitem>
     <para>
      When a single quotation mark in a string inside the function body is
      adjacent to the end of that string constant, for example:
<programlisting>
a_output := a_output || '' AND name LIKE ''''foobar''''''
</programlisting>
      The value appended to <literal>a_output</literal> would then be:
      <literal> AND name LIKE 'foobar'</literal>.
     </para>
     <para>
      In the dollar-quoting approach, this becomes:
<programlisting>
a_output := a_output || $$ AND name LIKE 'foobar'$$
</programlisting>
     </para>
    </listitem>
   </varlistentry>

   <varlistentry id="plpgsql-quote-tips-10-quot">
    <term>10 quotation marks</term>
    <listitem>
     <para>
      When you want two single quotation marks in a string constant (which
      accounts for 8 quotation marks) and this is adjacent to the end of that
      string constant (2 more).  You will probably only need that if
      you are writing a function that generates other functions, as in
      <xref linkend="plpgsql-porting-ex2"/>.
      For example:
<programlisting>
a_output := a_output || '' if v_'' ||
    referrer_keys.kind || '' like ''''''''''
    || referrer_keys.key_string || ''''''''''
    then return ''''''  || referrer_keys.referrer_type
    || ''''''; end if;'';
</programlisting>
      The value of <literal>a_output</literal> would then be:
<programlisting>
if v_... like ''...'' then return ''...''; end if;
</programlisting>
     </para>
     <para>
      In the dollar-quoting approach, this becomes:
<programlisting>
a_output := a_output || $$ if v_$$ || referrer_keys.kind || $$ like '$$
    || referrer_keys.key_string || $$'
    then return '$$  || referrer_keys.referrer_type
    || $$'; end if;$$;
</programlisting>
      where we assume we only need to put single quote marks into
      <literal>a_output</literal>, because it will be re-quoted before use.
     </para>
    </listitem>
   </varlistentry>
  </variablelist>

  </sect2>
  <sect2 id="plpgsql-extra-checks">
   <title>Additional Compile-Time and Run-Time Checks</title>

   <para>
    To