JOOQ / SQL如何基于外键选择最小日期

Question

I have a table called Foo which contains 3 columns, (id, time, barId) and I would like to select all fields from Foo where the time (stored as a timestamp) is the lowest one in a group of barId. For example if I had

Id, time, barId

1, 10am, 1

2, 11am, 1

3, 10am, 2

4, 9am, 2

I would expect to receive back rows 1 and 4.

Currently I am using

.select(FOO.ID, FOO.TIME.min, FOO.BAR_ID)
   .from(FOO)
   .where()
   .groupBy(FOO.BAR_ID)
   .fetchInto(Foo.class);

And I am receiving an error stating column "foo.id" must appear in the GROUP BY clause or be used in an aggregate function

Answer 1

The issue I had was that I was not grouping by the rows I was selecting.

The working code is

.select(FOO.ID, FOO.TIME.min, FOO.BAR_ID)
  .from(FOO)
  .where()
  .groupBy(FOO.ID, FOO.TIME, FOO.BAR_ID)
  .fetchInto(Foo.class);