我有一个函数返回表,它将多个调用的输出累积到另一个函数返回表。我想在返回结果之前对构建的表执行最终查询。目前我将其实现为 两个函数 ,一个累积,一个执行最终查询,这很难看:
CREATE OR REPLACE FUNCTION func_accu(LOCATION_ID INTEGER, SCHEMA_CUSTOMER TEXT)
RETURNS TABLE("networkid" integer, "count" bigint) AS $$
DECLARE
GATEWAY_ID integer;
BEGIN
FOR GATEWAY_ID IN
execute format(
'SELECT id FROM %1$I.gateway WHERE location_id=%2$L'
, SCHEMA_CUSTOMER, LOCATION_ID)
LOOP
RETURN QUERY execute format(
'SELECT * FROM get_available_networks_gw(%1$L, %2$L)'
, GATEWAY_ID, SCHEMA_CUSTOMER);
END LOOP;
END;
$$ LANGUAGE plpgsql;
CREATE OR REPLACE FUNCTION func_query(LOCATION_ID INTEGER, SCHEMA_CUSTOMER TEXT)
RETURNS TABLE("networkid" integer, "count" bigint) AS $$
DECLARE
BEGIN
RETURN QUERY execute format('
SELECT networkid, max(count) FROM func_accu(%2$L, %1$L) GROUP BY networkid;'
, SCHEMA_CUSTOMER, LOCATION_ID);
END;
$$ LANGUAGE plpgsql;
如何在 单一功能 中优雅地完成这项工作?
答案 0 :(得分:1)
两个函数都已简化和合并,还在USING
clause中提供了 value 参数:
CREATE OR REPLACE FUNCTION pg_temp.func_accu(_location_id integer, schema_customer text)
RETURNS TABLE(networkid integer, count bigint) AS
$func$
BEGIN
RETURN QUERY EXECUTE format('
SELECT f.networkid, max(f.ct)
FROM %I.gateway g
, get_available_networks_gw(g.id, $1) f(networkid, ct)
WHERE g.location_id = $2
GROUP BY 1'
, _schema_customer)
USING _schema_customer, _location_id;
END
$func$ LANGUAGE plpgsql;
呼叫:
SELECT * FROM func_accu(123, 'my_schema');
相关:
我正在使用函数(f(networkid, ct)
)返回的列的别名,因为您没有透露get_available_networks_gw()
的返回类型。您可以直接使用返回类型的列名。
,
子句中的逗号(FROM
)是CROSS JOIN LATERAL ...
的简短语法。需要Postgres 9.3或更高版本。
或者您可以运行此查询而不是函数:
SELECT f.networkid, max(f.ct)
FROM myschema.gateway g, get_available_networks_gw(g.id, 'my_schema') f(networkid, ct)
WHERE g.location_id = $2
GROUP BY 1;