sql - 尽管引用了表，但列名不明确

Question

尽管在一个非常相似的函数中没有这个问题，但我似乎在这个函数中遇到了这个问题，并且在这个特定的上下文中找不到关于这个问题的任何建议(我可以理解，哈哈)。如果有人可以提供任何建议或引用，将不胜感激。

错误:“列引用“customerid”不明确”

CREATE OR REPLACE FUNCTION update_FlightBooking(INTEGER, INTEGER, INTEGER, INTEGER, CHAR(1), TIMESTAMP, DECIMAL)
RETURNS TABLE
(
  BookingID INTEGER, 
  CustomerID INTEGER,
  FlightID INTEGER, 
  NumSeats INTEGER,
  Status CHAR(1),
  BookingTime TIMESTAMP,
  TotalCost DECIMAL
) AS $$

BEGIN
  IF NOT EXISTS (SELECT CustomerID FROM FlightBooking WHERE FlightBooking.CustomerID = $2) THEN
    INSERT INTO FlightBooking VAlUES($1, $2, $3, $4, $5, $6, $7);

  ELSE
    UPDATE FlightBooking AS fb
    SET NumSeats = NumSeats + $4, TotalCost = TotalCost + $7
    WHERE fb.CustomerID = $2;
  END IF;

  IF NOT EXISTS (SELECT CustomerID FROM LeadCustomer WHERE LeadCustomer.CustomerID = $2) THEN
    ROLLBACK;
  END IF;

  IF (check_Seats($3) < 0) THEN 
    ROLLBACK; 
  END IF;

  RETURN QUERY
    SELECT fb.BookingID, fb.CustomerID, fb.FlightID, fb.NumSeats, fb.Status, fb.BookingTime, fb.TotalCost 
    FROM FlightBooking AS fb WHERE fb.CustomerID = $1;
END;
$$
LANGUAGE plpgsql;

Answer 1

https://www.postgresql.org/docs/9.5/plpgsql-implementation.html说

By default, PL/pgSQL will report an error if a name in a SQL statement could refer to either a variable or a table column. You can fix such a problem by renaming the variable or column, or by qualifying the ambiguous reference, or by telling PL/pgSQL which interpretation to prefer.

这适用于 customerId在 IF NOT EXISTS (SELECT CustomerID ...