Enum specifying the syntaxes a filter can use. LIST_FILTER can be used internally.
| Enums | |
|---|---|
| FILTER_SYNTAX_UNSPECIFIED | A placeholder for an undefined filter syntax. | 
| PQL | PQL query syntax. Visit https://developers.google.com/ad-manager/api/pqlreference for PQL documentation and examples. | 
| LIST_FILTER | API list filtering syntax. Read about syntax and usage at https://developers.google.com/authorized-buyers/apis/guides/v2/list-filters. |