Update nested record with where condition in Bigquery

Question

I have a bigquery table \'metrics\' which has nested record fields One of the fields is called resource.labels which has key pair values as

Answer 1

Try below- should work

UPDATE `project.dataset.metrics`
SET resource = (
    SELECT AS STRUCT * REPLACE(
      ARRAY(
        SELECT AS STRUCT key, 
          IF(key='machinetype' and value='N/A', 'g1.small', value) as value
        FROM t.labels
      ) AS labels)
    FROM UNNEST([resource]) t
  )
WHERE true