-1

I have following two tables:

Table 1: Students
name:string,
age:integer,
class:integer,
number_of_allowed_trips:integer

Table 2: Trips
allowed_age:integer,
trip_name:string,
class:integer

I'm trying to assign for each student number of allowed trips based on some conditions. My query is:

UPDATE
  `mydataset.students` AS s
SET
  s.number_of_allowed_trips=(
  SELECT
    COUNT(*)
  FROM
    `mydataset.trips` AS t
  WHERE
    t.r.class= 9)
FROM
  `mydataset.trips` AS t
WHERE 
  r.name = 'Jack' 
  AND r.class = 9
  AND w.class = r.class

But this query doesn't work. What am I doing false? How can I get this code worked?

Mohny
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1 Answers1

0
UPDATE
  `mydataset.students` AS s
SET
  s.number_of_allowed_trips= (
  SELECT
    COUNT(*)
  FROM
    `mydataset.trips` AS t
  WHERE
    t.class = s.class
    AND s.age= 9  )
WHERE
  s.id=s.id

This works fine!

Mohny
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