ERROR: "syntax error at or near "." Position" (New LookML)

This is not actually a Looker bug, but an oversight or, perhaps, a needed feature.

When misplacing sql for sql_on in a join condition (note: join type is specified):

join: heap {

    type: left_outer

    relationship: one_to_one

    sql: ${site_visits.id} = ${heap.user_id}

    AND ${site_visits.type} = 'heap';;

  }

The SQL generated will bypass the join:

FROM site_visits

site_visits.id = heap.user_id

    AND site_visits.type = 'heap'

You might expect a validation alert from the New LookML, but since this is your typo under sql value, there won’t be one.

Instead, you need to replace the sql with a sql_on

join: heap {

    type: left_outer

    relationship: one_to_one

    sql_on: ${site_visits.id} = ${heap.user_id}

    AND ${site_visits.type} = 'heap';;

  }

or alternatively, specify the join under sql:

join: heap {

    type: left_outer

    relationship: one_to_one

    sql: LEFT JOIN heap ON ${site_visits.id} = ${heap.user_id}

    AND ${site_visits.type} = 'heap';;

  }

Of course, Looker could be smarter to recognize that I have specified type: left_outer join, which overlaps with a manual sql LEFT JOIN. Ideally, it would warn me of a sql keyword when type: is already specified.