fanout_on parameter specifies the Google BigQuery Legacy SQL
REPEATED subrecord on which a dimension or measure should fanout.
Google BigQuery Legacy SQL supports nested records in which a single record can hold multiple subrecords. Expressing these subrecords in Looker causes the result set to “fanout”, which means that the parent record gets repeated multiple times. In order for Looker to properly associate the normal data with the repeated data, you can specify the fanout relationship of a subrecord using the
Consider this example data table:
Data without the
citiesLived record may look like this:
However, adding the repeated
citiesLived record causes a fanout, where the
age data is repeated multiple times:
|Wilbur Wright||45||Kitty Hawk||1|
When modeling this type of data the
citiesLived record causes the fanout, so it is used in the
Note that both dimensions and measures must use
fanout_on if they include a repeated record in their calculation.