Provided by: postgresql-client-9.1_9.1.1-1_i386 bug

NAME

       FETCH - retrieve rows from a query using a cursor

SYNOPSIS

       FETCH [ direction [ FROM | IN ] ] cursor_name

       where direction can be empty or one of:

           NEXT
           PRIOR
           FIRST
           LAST
           ABSOLUTE count
           RELATIVE count
           count
           ALL
           FORWARD
           FORWARD count
           FORWARD ALL
           BACKWARD
           BACKWARD count
           BACKWARD ALL

DESCRIPTION

       FETCH retrieves rows using a previously-created cursor.

       A cursor has an associated position, which is used by FETCH. The cursor
       position can be before the first row of the query result, on any
       particular row of the result, or after the last row of the result. When
       created, a cursor is positioned before the first row. After fetching
       some rows, the cursor is positioned on the row most recently retrieved.
       If FETCH runs off the end of the available rows then the cursor is left
       positioned after the last row, or before the first row if fetching
       backward.  FETCH ALL or FETCH BACKWARD ALL will always leave the cursor
       positioned after the last row or before the first row.

       The forms NEXT, PRIOR, FIRST, LAST, ABSOLUTE, RELATIVE fetch a single
       row after moving the cursor appropriately. If there is no such row, an
       empty result is returned, and the cursor is left positioned before the
       first row or after the last row as appropriate.

       The forms using FORWARD and BACKWARD retrieve the indicated number of
       rows moving in the forward or backward direction, leaving the cursor
       positioned on the last-returned row (or after/before all rows, if the
       count exceeds the number of rows available).

       RELATIVE 0, FORWARD 0, and BACKWARD 0 all request fetching the current
       row without moving the cursor, that is, re-fetching the most recently
       fetched row. This will succeed unless the cursor is positioned before
       the first row or after the last row; in which case, no row is returned.

           Note
           This page describes usage of cursors at the SQL command level. If
           you are trying to use cursors inside a PL/pgSQL function, the rules
           are different -- see Section 39.7, "Cursors", in the documentation.

PARAMETERS

       direction
           direction defines the fetch direction and number of rows to fetch.
           It can be one of the following:

           NEXT
               Fetch the next row. This is the default if direction is
               omitted.

           PRIOR
               Fetch the prior row.

           FIRST
               Fetch the first row of the query (same as ABSOLUTE 1).

           LAST
               Fetch the last row of the query (same as ABSOLUTE -1).

           ABSOLUTE count
               Fetch the count'th row of the query, or the abs(count)'th row
               from the end if count is negative. Position before first row or
               after last row if count is out of range; in particular,
               ABSOLUTE 0 positions before the first row.

           RELATIVE count
               Fetch the count'th succeeding row, or the abs(count)'th prior
               row if count is negative.  RELATIVE 0 re-fetches the current
               row, if any.

           count
               Fetch the next count rows (same as FORWARD count).

           ALL
               Fetch all remaining rows (same as FORWARD ALL).

           FORWARD
               Fetch the next row (same as NEXT).

           FORWARD count
               Fetch the next count rows.  FORWARD 0 re-fetches the current
               row.

           FORWARD ALL
               Fetch all remaining rows.

           BACKWARD
               Fetch the prior row (same as PRIOR).

           BACKWARD count
               Fetch the prior count rows (scanning backwards).  BACKWARD 0
               re-fetches the current row.

           BACKWARD ALL
               Fetch all prior rows (scanning backwards).

       count
           count is a possibly-signed integer constant, determining the
           location or number of rows to fetch. For FORWARD and BACKWARD
           cases, specifying a negative count is equivalent to changing the
           sense of FORWARD and BACKWARD.

       cursor_name
           An open cursor's name.

OUTPUTS

       On successful completion, a FETCH command returns a command tag of the
       form

           FETCH count

       The count is the number of rows fetched (possibly zero). Note that in
       psql, the command tag will not actually be displayed, since psql
       displays the fetched rows instead.

NOTES

       The cursor should be declared with the SCROLL option if one intends to
       use any variants of FETCH other than FETCH NEXT or FETCH FORWARD with a
       positive count. For simple queries PostgreSQL will allow backwards
       fetch from cursors not declared with SCROLL, but this behavior is best
       not relied on. If the cursor is declared with NO SCROLL, no backward
       fetches are allowed.

       ABSOLUTE fetches are not any faster than navigating to the desired row
       with a relative move: the underlying implementation must traverse all
       the intermediate rows anyway. Negative absolute fetches are even worse:
       the query must be read to the end to find the last row, and then
       traversed backward from there. However, rewinding to the start of the
       query (as with FETCH ABSOLUTE 0) is fast.

       DECLARE(7) is used to define a cursor. Use MOVE(7) to change cursor
       position without retrieving data.

EXAMPLES

       The following example traverses a table using a cursor:

           BEGIN WORK;

           -- Set up a cursor:
           DECLARE liahona SCROLL CURSOR FOR SELECT * FROM films;

           -- Fetch the first 5 rows in the cursor liahona:
           FETCH FORWARD 5 FROM liahona;

            code  |          title          | did | date_prod  |   kind   |  len
           -------+-------------------------+-----+------------+----------+-------
            BL101 | The Third Man           | 101 | 1949-12-23 | Drama    | 01:44
            BL102 | The African Queen       | 101 | 1951-08-11 | Romantic | 01:43
            JL201 | Une Femme est une Femme | 102 | 1961-03-12 | Romantic | 01:25
            P_301 | Vertigo                 | 103 | 1958-11-14 | Action   | 02:08
            P_302 | Becket                  | 103 | 1964-02-03 | Drama    | 02:28

           -- Fetch the previous row:
           FETCH PRIOR FROM liahona;

            code  |  title  | did | date_prod  |  kind  |  len
           -------+---------+-----+------------+--------+-------
            P_301 | Vertigo | 103 | 1958-11-14 | Action | 02:08

           -- Close the cursor and end the transaction:
           CLOSE liahona;
           COMMIT WORK;

COMPATIBILITY

       The SQL standard defines FETCH for use in embedded SQL only. The
       variant of FETCH described here returns the data as if it were a SELECT
       result rather than placing it in host variables. Other than this point,
       FETCH is fully upward-compatible with the SQL standard.

       The FETCH forms involving FORWARD and BACKWARD, as well as the forms
       FETCH count and FETCH ALL, in which FORWARD is implicit, are PostgreSQL
       extensions.

       The SQL standard allows only FROM preceding the cursor name; the option
       to use IN, or to leave them out altogether, is an extension.

SEE ALSO

       CLOSE(7), DECLARE(7), MOVE(7)