Postgresql: EXECUTE sql_cmd merge with CREATE TEMP TABLE temp_tbl AS SELECT - postgresql

Question

Soo, here is the thing, I am using in my DB methods 2 approaches:
1.) Is compose and SQL query from various string, depending on what I need to filter out:
sql_cmd := 'SELECT count(*) FROM art_short_term_finished WHERE (entry_time <= ''' || timestamp_up || ''' AND exit_time >= ''' || timestamp_down || ''') AND ' || time_filter || ' AND entry_zone = ' || zone_parameter || ' AND park_uuid = ' || park_id_p || '';
EXECUTE sql_cmd INTO shortterm_counter;
2.) Copy part of the big table, into smaller temp table and work with it:
-- Get the data from FPL into smaller table for processing
DROP TABLE IF EXISTS temp_fpl_filtered;
CREATE TEMP TABLE temp_fpl_filtered AS SELECT car_id FROM flexcore_passing_log fpl WHERE fpl.zone_leaved = '0' AND fpl.status IN (SELECT status_id FROM fpl_ok_statuses) AND fpl.park_uuid = park_id_p AND (fpl.datetime BETWEEN row_i.start_d AND row_i.end_d);
But what If I want to mix those two?
I want to have the SELECT after CREATE TEMP TABLE temp_fpl_filtered AS to have different WHERE clauses depending on input parameters of stored procedure, without having to write the same statement xy times in one stored procedure.
But my approach:
-- art class is shortterm, check shortterm history
IF art_class_p = 1 OR article_p = 0 THEN
-- create temporary table derivated from shortterm history
IF article_p = 0 THEN
article_p_filter := '';
ELSE
article_p_filter := ' AND article_id = ' || article_p;
END IF;
short_cmd := 'SELECT car_id, article_id, entry_time, exit_time FROM art_short_term_finished WHERE zone_leaved = ''0'' AND status IN (SELECT status_id FROM fpl_ok_statuses) ''' || article_p_filter || ''' AND park_uuid = ''' || park_id_p || ''' AND (entry_time <= ''' || timestamp_up || ''' AND exit_time >= ''' || timestamp_down || ''')';
DROP TABLE IF EXISTS temp_short_full;
CREATE TEMP TABLE temp_short_full AS short_cmd;
--EXECUTE sql_cmd INTO shortterm_counter;
END IF;
throws me an exception when I try to inser stored procedure:
psql:report_parking_average.sql:107: ERROR: syntax error at or near "short_cmd"
LINE 50: CREATE TEMP TABLE temp_fpl_filtered AS short_cmd;
^
Also, the another try:
EXECUTE short_cmd INTO TEMP TABLE temp_short_full;
is not working..

Answer 1

You need to include the CREATE TABLE part into the SQL you generate:
short_cmd := 'CREATE TEMP TABLE temp_short_full AS SELECT car_id, article_id, entry_time, exit_time FROM art_short_term_finished WHERE zone_leaved = ''0'' AND status IN (SELECT status_id FROM fpl_ok_statuses) ''' || article_p_filter || ''' AND park_uuid = ''' || park_id_p || ''' AND (entry_time <= ''' || timestamp_up || ''' AND exit_time >= ''' || timestamp_down || ''')';
DROP TABLE IF EXISTS temp_short_full;
execute short_cmd;