query and subquery in python

[artistlikeu]

dear all
i am using postgresql data base....
is it possible to write a subquery in inside the main query in python program....
for example something like this.....

courses = db.query("select course_id, student_id, select course_coordinator from teachers join course on teacher.course_id=course.course_id, start_date from school)"

subquery .....student_id, select course_coordinator from teachers join course on teacher.course_id=course.course_id..... is giving one attribute for main QUERY and it is required.......

will this query work..... if not any suggestion to write subquery.....
thnx

[michaelb]

python or not, this is just an interface you're using to communicate with the database.

Write your query and test it with the most simple client: psql.
If it works, then plug it in into your python code.

I am not sure what you are trying to achieve with the sql you posted.
Here's a simple example of query using subquery

 
select name, phone from student where student.student_id in
-- run a subquery to get the list of ids for the query
( select student_id from enrollment where enrollment_date > '2007-01-01' )
 

Sometimes a subquery can be replaced with a join.

Look at this, it may help you

http://www.postgresql.org/docs/8.0/i...-subquery.html