绝对新手问题。在课程中我们使用PostgreSQL函数,例如:
Original Answer翻译成"最初的回答"
CREATE FUNCTION Raptor_lastSurveyDate1(bigint) RETURNS date As $$
SELECT max(date) FROM raptor_surveys WHERE nest=$1;
$$ LANGUAGE SQL
或者:
CREATE FUNCTION Raptor_lastSurveyDate2(bigint) RETURNS date As $$
SELECT date FROM raptor_surveys WHERE nest=$1 ORDER BY date DESC LIMIT 1;
$$ LANGUAGE SQL
这个$1参数是什么意思? 补充:最初的回答。
select * from raptor_surveys delivers this table: