Question

I am using access,and I have two tables:

point:

id,x,y
1 32432432 143423232
2 32432443 143423300

line:

id startPoint endPoint
1  1          2

Now, when I query the line,I want the returned table will contain both the x,y of the startPoint and the endPoint.

I have tried the join:

select line.*,point.x as x1,point.y as y1 from line as line join point as point on line.startPoint=point.id where line.id=1;

Then I can get the following result which only contain the startPoint.

id startPoint endPoint x1 y1
1  1          2        ......

Then how to retrive the endPoint while I want the result like this(x2 y2 is the coordinate of the endPoint):

id startPoint endPoint x1 y1 x2 y2
1  1          2        ......

I tried two join,but it does not work.

select line.*,point1.x as x1,point1.y as y1,point2.x as x2,point.y as y2 from line as line left join point1 as point on line.startPoint=point1.id  left join point as point2 on line.endPoint=point2.id where line.id=1;

Answer 1

Access has weird syntax rules for multiple joins. You have to put them in parentheses like so.

select line.*, point1.x as x1,point1.y as y1,
    point2.x as x2, point.y as y2
from (line as line
left join point as point1
on line.startPoint = point1.id)
left join point as point2
on line.endPoint = point2.id
where line.id = 1;

Each additional join requires another left paren before the first table and a right paren after the second-to-last join.