Create unidirectional sample set (table) from bi-directional samples

bidir2unidir.sql

-- PostgreSQL
DROP TABLE IF EXISTS uview5_uni;
CREATE TABLE uview5_uni AS
SELECT
	start_time,
	CASE e WHEN  1 THEN mac_addr_1 ELSE mac_addr_2 END src_mac_addr,
	CASE e WHEN  1 THEN mac_addr_2 ELSE mac_addr_1 END des_mac_addr,
	CASE e WHEN  1 THEN byte_count_1 ELSE byte_count_2 END byte_count,
	CASE e WHEN  1 THEN packet_count_1 ELSE packet_count_2 END packet_count,
	last_time,
	vlan_id,vlan_id2,mpls_tag,mpls_tag2,
	application_id,
	CASE e WHEN  1 THEN ip_addr_1 ELSE ip_addr_2 END src_ip_addr,
	CASE e WHEN  1 THEN ip_addr_2 ELSE ip_addr_1 END dst_ip_addr,
	CASE e WHEN  1 THEN port_1 ELSE port_2 END src_port,
	CASE e WHEN  1 THEN port_2 ELSE port_1 END dst_port,
	ip_protocol,
	zero_window_events,
	fragmented_count,
	diff_serv,
	flags,
	flow_id,
	ethertype
FROM uview5, (VALUES (1),(2)) AS ep(e)
WHERE 
 ( e=1 AND packet_count_1 > 0 ) OR ( e=2 AND packet_count_2 > 0 );

proc.sql

CREATE OR REPLACE FUNCTION bi2uni(tbl text) 
RETURNS VOID LANGUAGE plpgsql AS $$BEGIN
-- PostgreSQL
EXECUTE
'CREATE TABLE '||tbl||'_uni AS
SELECT
	start_time,
	CASE e WHEN  1 THEN mac_addr_1 ELSE mac_addr_2 END src_mac_addr,
	CASE e WHEN  1 THEN mac_addr_2 ELSE mac_addr_1 END des_mac_addr,
	CASE e WHEN  1 THEN byte_count_1 ELSE byte_count_2 END byte_count,
	CASE e WHEN  1 THEN packet_count_1 ELSE packet_count_2 END packet_count,
	last_time,
	vlan_id,vlan_id2,mpls_tag,mpls_tag2,
	application_id,
	CASE e WHEN  1 THEN ip_addr_1 ELSE ip_addr_2 END src_ip_addr,
	CASE e WHEN  1 THEN ip_addr_2 ELSE ip_addr_1 END dst_ip_addr,
	CASE e WHEN  1 THEN port_1 ELSE port_2 END src_port,
	CASE e WHEN  1 THEN port_2 ELSE port_1 END dst_port,
	ip_protocol,
	zero_window_events,
	fragmented_count,
	diff_serv,
	flags,
	flow_id,
	ethertype
FROM '||tbl||', (VALUES (1),(2)) AS ep(e)
WHERE 
 ( e=1 AND packet_count_1 > 0 ) OR ( e=2 AND packet_count_2 > 0 );
CREATE INDEX '||tbl||'_uni_idx ON '||tbl||'_uni(last_time);
 ';
 END;$$;