Question

我试图编写一个MySQL查询，根据查询到TABLE2的结果从TABLE1中选择结果。像这样：

SELECT route_id FROM trips WHERE trip_id = 
SELECT trip_id  FROM stop_times WHERE 
stop_id=<ID GOES HERE> LIMIT 1

但这不起作用，所以我尝试了这个：

SELECT route_id FROM trips WHERE trip_id 
INNER JOIN(
SELECT trip_id  FROM stop_times WHERE stop_id=<ID GOES HERE> LIMIT 1
)

它也不起作用。我收到此错误：

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'INNER JOIN(SELECT trip_id  FROM stop_times WHERE stop_id="16817" LIMIT 1)
LIMIT 0' at line 1

Answer 1

您的原始查询应如下所示：

SELECT t.route_id
FROM trips t
WHERE t.trip_id = (SELECT st.trip_id
                   FROM stop_times st
                   WHERE st.stop_id = <ID GOES HERE>
                   LIMIT 1
                  );

我认为这通常会写成：

SELECT t.route_id
FROM stop_times st JOIN
     trips t
     ON t.trip_id = st.trip_id
WHERE st.stop_id = <ID GOES HERE>
LIMIT 1;

这假定您想要返回一行。

Answer 2

你的子查询应该是：

SELECT route_id 
FROM trips 
WHERE trips.trip_id =
( 
    SELECT stop_times.trip_id  
    FROM stop_times 
    WHERE stop_id = <ID GOES HERE> 
    LIMIT 1
)

Answer 3

有两种选择：

SELECT route_id FROM trips WHERE trip_id in (SELECT trip_id  FROM stop_times WHERE stop_id=<ID GOES HERE> LIMIT 1)

或者更容易：

select t.route_id from trips t, stop_times s where t.trip_id = s.trip_id and s.stop_id= <ID GOES HERE> LIMIT 1

对WHERE比较器的SQL多个查询

3 个答案: