Postgresql ss我的关键问题是，假设我们必须在规则中执行此操作，那么如何修改查询以使foobar中的_值列（在规则中的WITH中定义）对SELECT可见？现在_值似乎在规则中传递给SELECT为NULL或VOID。 BEGIN; CREATE OR REPLACE

ss我的关键问题是，假设我们必须在规则中执行此操作，那么如何修改查询以使foobar中的_值列（在规则中的WITH中定义）对SELECT可见？现在_值似乎在规则中传递给SELECT为NULL或VOID。

BEGIN;

CREATE OR REPLACE FUNCTION debug(anyelement) RETURNS bool AS $$

pg_raise('notice', 'debug(): ' . json_encode($args[0]));

RETURN TRUE;

$$ LANGUAGE PLPHP IMMUTABLE STRICT;

CREATE TABLE foo_table (c1 text);

CREATE OR REPLACE RULE foo_update_rule AS ON UPDATE TO foo_table DO INSTEAD
(
    WITH foobar_update AS
    (
        SELECT unnest('{a,b}'::text[]) AS _value, debug('update_inner'::text)
    )
    SELECT *, debug('update_outer_1'::text), debug('update_outer_2 -> '::text || _value::text) FROM foobar_update;


SELECT

        ( ROW(FALSE,FALSE) IN ( SELECT 
                        debug('update2_outer_1'::text), debug('update2_outer_2 -> '::text || _value::text)
                   FROM ( SELECT unnest('{a,b}'::text[]) AS _value, debug('update_inner'::text) ) AS foobar_update2     ))

);

-----------------------------------------------

WITH foobar_select AS
(
    SELECT unnest('{a,b}'::text[]) AS _value, debug('select_inner'::text)
)
SELECT *, debug('select_outer_1'::text), debug('select_outer_2 -> '::text || _value::text), debug('select_outer_3'::text) FROM foobar_select;

UPDATE foo_table SET c1 = NULL where c1 = 'aaa';

ROLLBACK;

NOTICE:  plphp: debug(): "select_inner"
NOTICE:  plphp: debug(): "select_outer_1"
NOTICE:  plphp: debug(): "select_outer_3"
NOTICE:  plphp: debug(): "select_outer_2 -> a"
NOTICE:  plphp: debug(): "select_outer_2 -> b"
NOTICE:  plphp: debug(): "update_inner"
NOTICE:  plphp: debug(): "update_outer_1"
NOTICE:  plphp: debug(): "update2_outer_1"
NOTICE:  plphp: debug(): "update_inner"

NOTICE:  plphp: debug(): "update_outer_2 -> a"
NOTICE:  plphp: debug(): "update_outer_2 -> b"

NOTICE:  plphp: debug(): "update2_outer_2 -> a"
NOTICE:  plphp: debug(): "update2_outer_2 -> b"