How to use subquery In Sphinx's multi-valued attributes (MVA) for query type - postgresql

Question

My database is PostgreSQL, and I want to use Sphinx Search Engines to index my data;
How can i use sql_attr_multi to fetch the relationship data?
The tables in postgresql, schemas is:
crm=# \d orders
Table "orders"
Column | Type | Modifiers
-----------------+-----------------------------+----------------------------------------
id | bigint | not null
trade_id | bigint | not null
item_id | bigint | not null
price | numeric(10,2) | not null
total_amount | numeric(10,2) | not null
subject | character varying(255) | not null default ''::character varying
status | smallint | not null default 0
created_at | timestamp without time zone | not null default now()
updated_at | timestamp without time zone | not null default now()
Indexes:
"orders_pkey" PRIMARY KEY, btree (id)
"orders_trade_id_idx" btree (trade_id)
crm=# \d trades
Table "trades"
Column | Type | Modifiers
-----------------------+-----------------------------+---------------------------------------
id | bigint | not null
operator_id | bigint | not null
customer_id | bigint | not null
category_ids | bigint[] | not null
total_amount | numeric(10,2) | not null
discount_amount | numeric(10,2) | not null
created_at | timestamp without time zone | not null default now()
updated_at | timestamp without time zone | not null default now()
Indexes:
"trades_pkey" PRIMARY KEY, btree (id)
The Sphinx's config is:
source trades_src
{
type = pgsql
sql_host = 10.10.10.10
sql_user = ******
sql_pass = ******
sql_db = crm
sql_port = 5432
sql_query = \
SELECT id, operator_id, customer_id, category_ids, total_amount, discount_amount, \
date_part('epoch',created_at) AS created_at, \
date_part('epoch',updated_at) AS updated_at \
FROM public.trades;
#attributes
sql_attr_bigint = operator_id
sql_attr_bigint = customer_id
sql_attr_float = total_amount
sql_attr_float = discount_amount
sql_attr_multi = bigint category_ids from field category_ids
#sql_attr_multi = bigint order_ids from query; SELECT id FROM orders
#how can i add where condition is the query for orders? eg. WHERE trade_id = ?
sql_attr_timestamp = created_at
sql_attr_timestamp = updated_at
}
I used MVA (multi-valued attributes) on category_ids field, and it is the ARRAY type in Postgresql.
But I donot know How to define MVA on order_ids. It will be through subquery?

Answer 1

Copied from sphinx forum....
sql_attr_multi = bigint order_ids from query; SELECT trade_id,id FROM orders ORDER BY trade_id
The first column of the query is the sphinx 'document_id' (ie the id in main sql_query)
The second column is the value to insert into the MVA array for that document.
(The ORDER BY might not strictly be needed, but sphinx is much quicker at processing the data if ordered by document_id IIRC)