row)
</programlisting>
   The subquery must return a single column.
   If the subquery's output column is of a non-array type, the resulting
   one-dimensional array will have an element for each row in the
   subquery result, with an element type matching that of the
   subquery's output column.
   If the subquery's output column is of an array type, the result will be
   an array of the same type but one higher dimension; in this case all
   the subquery rows must yield arrays of identical dimensionality, else
   the result would not be rectangular.
  </para>

  <para>
   The subscripts of an array value built with <literal>ARRAY</literal>
   always begin with one.  For more information about arrays, see
   <xref linkend="arrays"/>.
  </para>

  </sect2>

  <sect2 id="sql-syntax-row-constructors">
   <title>Row Constructors</title>

   <indexterm>
    <primary>composite type</primary>
    <secondary>constructor</secondary>
   </indexterm>

   <indexterm>
    <primary>row type</primary>
    <secondary>constructor</secondary>
   </indexterm>

   <indexterm>
    <primary>ROW</primary>
   </indexterm>

   <para>
    A row constructor is an expression that builds a row value (also
    called a composite value) using values
    for its member fields.  A row constructor consists of the key word
    <literal>ROW</literal>, a left parenthesis, zero or more
    expressions (separated by commas) for the row field values, and finally
    a right parenthesis.  For example:
<programlisting>
SELECT ROW(1,2.5,'this is a test');
</programlisting>
    The key word <literal>ROW</literal> is optional when there is more than one
    expression in the list.
   </para>

   <para>
    A row constructor can include the syntax
    <replaceable>rowvalue</replaceable><literal>.*</literal>,
    which will be expanded to a list of the elements of the row value,
    just as occurs when the <literal>.*</literal> syntax is used at the top level
    of a <command>SELECT</command> list (see <xref linkend="rowtypes-usage"/>).
    For example, if table <literal>t</literal> has
    columns <literal>f1</literal> and <literal>f2</literal>, these are the same:
<programlisting>
SELECT ROW(t.*, 42) FROM t;
SELECT ROW(t.f1, t.f2, 42) FROM t;
</programlisting>
   </para>

   <note>
    <para>
     Before <productname>PostgreSQL</productname> 8.2, the
     <literal>.*</literal> syntax was not expanded in row constructors, so
     that writing <literal>ROW(t.*, 42)</literal> created a two-field row whose first
     field was another row value.  The new behavior is usually more useful.
     If you need the old behavior of nested row values, write the inner
     row value without <literal>.*</literal>, for instance
     <literal>ROW(t, 42)</literal>.
    </para>
   </note>

   <para>
    By default, the value created by a <literal>ROW</literal> expression is of
    an anonymous record type.  If necessary, it can be cast to a named
    composite type &mdash; either the row type of a table, or a composite type
    created with <command>CREATE TYPE AS</command>.  An explicit cast might be needed
    to avoid ambiguity.  For example:
<programlisting>
CREATE TABLE mytable(f1 int, f2 float, f3 text);

CREATE FUNCTION getf1(mytable) RETURNS int AS 'SELECT $1.f1' LANGUAGE SQL;

-- No cast needed since only one getf1() exists
SELECT getf1(ROW(1,2.5,'this is a test'));
 getf1
-------
     1
(1 row)

CREATE TYPE myrowtype AS (f1 int, f2 text, f3 numeric);

CREATE FUNCTION getf1(myrowtype) RETURNS int AS 'SELECT $1.f1' LANGUAGE SQL;

-- Now we need a cast to indicate which function to call:
SELECT getf1(ROW(1,2.5,'this is a test'));
ERROR:  function getf1(record) is not unique

SELECT getf1(ROW(1,2.5,'this is a test')::mytable);
 getf1
-------
     1
(1 row)

SELECT getf1(CAST(ROW(11,'this is a test',2.5) AS myrowtype));
 getf1
-------
    11
(1 row)
</programlisting>
  </para>

  <para>
   Row constructors can be used to build composite values to be stored
   in a composite-type table