Re: Execute format Insert sql failing with query string argument of EXECUTE is null for column with timestamp with timezone

2017-08-26 7:38 GMT+02:00 anand086 <anand086(at)gmail(dot)com>:

> I am a Postgres Newbie and looking for some help on how I can achieve to
> have null in child table column with "timestamp with time zone" when using
> EXECUTE format insert sql. I have a range partitioned table by day and want
> to insert data into the current day's partition. Trigger is available on
> the master table based on which the data would be directed to current day's
> partition. But I want to directly insert data into the child table rather
> than using trigger to have it done. We have a table which maintains the
> child table names along with its low and high date values. Below is kind of
> what I am doing --
>
> CREATE OR REPLACE FUNCTION test_tab_func (BIGINT, TIMESTAMP WITH TIME ZONE, TIMESTAMP WITH TIME ZONE)
> RETURNS boolean
> AS
> $BODY$
> DECLARE
> _id ALIAS FOR $1;
> _time ALIAS for $2;
> _parttime ALIAS for $3;
> _partition text;
> _z RECORD;
> BEGIN
>
> SELECT child_table_name into STRICT _partition from child_tables where parent_table_name='test_tab' and part_low=_parttime;
>
> FOR _z IN SELECT table_id,
> analyzed_on
> FROM test_tab
> WHERE schemaname = 'app' LOOP
> EXECUTE format('INSERT INTO dev.%s (id,
> time,
> table_id,
> analyzed_on)
> VALUES ('||_id|||',
> '''||_time ||''',
> '||_z.table_id||',
> '||_z.analyzed_on||')',_partition);
> END LOOP;
> RETURN true;
> END;
> $BODY$
> LANGUAGE plpgsql;
>
> The table "test_tab" has few rows with analyzed_on as null. When I run the
> function I get the below error ERROR: query string argument of EXECUTE is
> null. I way which I know is using COALESCE. But how do I achieve null value
> in my child table using COALESCE. I am not able to figure it out.

any parameter can be NULL: _id, _time, _z.table_id, _z.analyzed_on

NULL is same as empty string on Oracle, but on PostgreSQL NULL is NULL
every where.

You can use USING clause for better readability and robustness against NULLs

EXECUTE format('INSERT INTO dev.%s (id,
time,
table_id,
analyzed_on)
VALUES ($1, $2, $3,
$4)',_partition)

USING _id, _time, _z.table_id, _z.analyzed_on;

Regards

Pavel

>
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> query string argument of EXECUTE is null for column with timestamp with
> timezone
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