CURRENT ROW</literal>; it sets the frame to be all rows from the partition start

up through the current row's last <firstterm>peer</firstterm> (a row

that the window's <literal>ORDER BY</literal> clause considers

equivalent to the current row), orall rows if there

is no <literal>ORDER BY</literal>.

equivalent to the current row;all rows are peers if there

is no <literal>ORDER BY</literal>).

In general, <literal>UNBOUNDED PRECEDING</literal> means that the frame

starts with the first row of the partition, and similarly

<literal>UNBOUNDED FOLLOWING</literal> means that the frame ends with the last

is an integer indicating that the frame starts or ends that many peer

groups before or after the current row's peer group, where

a <firstterm>peer group</firstterm> is a group of rows that are

equivalent according to <literal>ORDER BY</literal>.

equivalent according tothe window's<literal>ORDER BY</literal> clause.

In <literal>RANGE</literal> mode, use of

an <replaceable>offset</replaceable> option requires that there be

exactly one <literal>ORDER BY</literal> column in the window definition.

ends the specified number of <firstterm>peer groups</firstterm>

before or after the current row's peer group, where a peer group is a

set of rows that are equivalent in the <literal>ORDER BY</literal>

ordering. (If there is no <literal>ORDER BY</literal>, the whole

partition is one peer group.)

ordering. (There must be an <literal>ORDER BY</literal> clause

in the window definition to use <literal>GROUPS</literal> mode.)

</para>

</listitem>

<listitem>