mysql - sql查询减号运算

Question

SELECT flight_id, depart, arr, price 
FROM user.flightdb t2 LEFT JOIN
     user.booking t1
     ON t1.flightID = t2.flight_id
WHERE t2.source = 1 and t2.dest = 4 and
      t1.date = "02/02/2016" and t1.flightID IS NULL;

我想从flightdb(表)中选择那些应该具有给定来源和目的地的flight_id，并且其中没有出现在特定日期的预订(表)中。

那么mysql中的查询是什么

Answer 1

您可以使用左联接，但第二个表上的条件需要位于on 子句中。另外，您应该使用正确的日期格式:

SELECT flight_id, depart, arr, price 
FROM user.flightdb t2 LEFT JOIN
     user.booking t1
     ON t1.flightID = t2.flight_id and t1.date = '2016-02-02'
WHERE t2.source = 1 and t2.dest = 4 and t1.flightID IS NULL;