Upsert

# Wrap everything in a `SELECT` to also display the
# entire inserted structure.
SELECT (
    INSERT Text {
        title := 'Anonymous post',
        body := 'Showcasing "select-or-insert" pattern.',
        author := (
            # Although it may seem more natural to think
            # of it as a select-or-insert command, it is
            # actually implemented as an
            # insert-or-select one.
            INSERT User {
                name := 'Anonymous',
                email := 'anonymous@edgedb.com'
            } UNLESS CONFLICT ON .email ELSE User
              # No need to add a FILTER, because the
              # User here is referring to the
              # conflicting User from the INSERT part.
        )
    }
) {
    title,
    body,
    post_date,
    author: {
        id,
        name,
        email
    }
}

SELECT (
    INSERT Text {
        title := 'Correction',
        body :=
          'Actually it should be "insert-or-select" pattern.',
        author := (
            INSERT User {
                name := 'Anonymous',
                email := 'anonymous@edgedb.com'
            } UNLESS CONFLICT ON .email ELSE User
        )
    }
) {
    title,
    body,
    post_date,
    author: {
        id,
        name,
        email
    }
}