Question

我有查询功能。如果条件为true，则用新值更新一行。

我进行查询：

SELECT * FROM transfer_flight(41313, '2017-08-15 20:00:00+05');

我得到一个错误：

错误：表“航班”缺少FROM子句条目第1行：SELECT（flights.scheduled_departure <$ 2） ^ 查询：SELECT（flights.scheduled_departure <$ 2）背景：IF处的PL / pgSQL函数transfer_flight（integer，timestamp with time> zone）在第7行位于

CREATE OR REPLACE FUNCTION flightFunc(
    flight_identificator INTEGER, 
    new_timestamp timestamp with time zone) 
RETURNS TABLE(
    flight_id INTEGER,
    flight_no CHARACTER(6),
    departure_airport character(3),
    scheduled_departure timestamp with time zone,
    arrival_airport character(3),
    scheduled_arrival timestamp with time zone
)
LANGUAGE plpgsql
AS $$
DECLARE 
    flight_d timestamp with time zone =  scheduled_arrival - 
scheduled_departure;

BEGIN

    IF (flights.scheduled_departure < $2)
    THEN
        UPDATE flights
            scheduled_departure = $2,
            scheduled_arrival = $2 + flight_d
        FROM flights
        WHERE flights.flight_id = $1
        RETURNING 
            flights.flight_id,  
            flights.flight_no,
            flights.departure_airport,
            flights.scheduled_departure,
            flights.arrival_airport,        
            flights.scheduled_arrival;
    END IF;

END;
$$;

结果，我只需要使用输入flight_identificator更新一行

Answer 1

删除FROM子句！就是CROSS JOIN。并且您需要SET。所以：

UPDATE flights
    SET scheduled_departure = $2,
        scheduled_arrival = $2 + flight_d
    WHERE flights.flight_id = $1
RETURNING 
    flights.flight_id,  
    flights.flight_no,
    flights.departure_airport,
    flights.scheduled_departure,
    flights.arrival_airport,        
    flights.scheduled_arrival;

Answer 2

在我看来，您应该摆脱_GNU_SOURCE变量和flight_d块，然后将逻辑移至查询本身，例如：

IF

如何修复“缺少表的FROM子句条目”？

2 个答案: