Hey 👋

fixes #1094.

Running the following query:

const result = await ctx.db
  .selectFrom('person')
  .leftJoin('toy', 'person.id', 'toy.id')
  .selectAll('person')
  .selectAll('toy')
  .execute()

On the 4 core dialects in our tests,
yields the following values for the shared id column:

As you can see, pg's results take person.id values, and not toy.id values. Other dialects do the opposite.

To align pg results with the other dialects, this PR uses rowMode: 'array' in PostgresDriver to get the raw values and produce objects that take the last value of a column with the same name. This is a breaking change for PostgreSQL users who relied on the default behavior of pg.

This PR doesn't handle the .selectAll() AND .selectAll(['person', 'toy']) cases. Here we'll get a union of all possible values of a shared column which is not accurate, but can be $narrowType'd. .selectAll(['person', 'toy']) can be solved with compile-time array recursion (which afaik is not that performant - not worth it??). .selectAll() requires a lot of testing - probably affected by order of introduction of tables to query context - if so, will require a huge refactor to TB[] and basically most types.

We can recommend our users to use multiple single-table calls, as the tightest option.
We can deprecate the multi-table variant and even the empty variant of selectAll.

Should we allow users to switch back to pg's default row processing with a flag in the dialect config?