SOQL Operation Limitations

Some Tooling API objects have SOQL limitations.
These objects in Tooling API don’t support SOQL operations COUNT(), GROUP BY, LIMIT, LIMIT OFFSET, OR, NOT, and INCLUDES.
  • CompactLayoutInfo
  • CompactLayoutItemInfo
  • DataType
  • EntityDefinition
  • EntityLimit
  • EntityParticle
  • FieldDefinition
  • Publisher
  • RelationshipDomain
  • RelationshipInfo
  • SearchLayout
  • ServiceFieldDataType
  • StandardAction
  • TimeSheetTemplate
  • UserEntityAccess
  • UserFieldAccess

The unsupported operations for these objects return errors or incorrect results, as these examples illustrate.

GROUP BY
Example Query: SELECT COUNT(qualifiedapiname), isfeedenabled FROM EntityDefinition GROUP BY isfeedenabled
Error Returned: The requested operation is not yet supported by this SObject storage type, contact salesforce.com support for more information.
LIMIT, LIMIT OFFSET
Example Queries:
SELECT qualifiedapiname FROM EntityDefinition LIMIT 5
SELECT qualifiedapiname FROM EntityDefinition LIMIT 5 OFFSET 10
An incorrect result is returned because LIMIT and LIMIT OFFSET are ignored.
NOT
Example Query: SELECT qualifiedapiname FROM EntityDefinition WHERE qualifiedapiname!='Account'
Error Returned: Only equals comparisons permitted
OR
Example Query: SELECT qualifiedapiname, keyprefix FROM EntityDefinition WHERE isdeletable=true OR (isfeedenabled=false AND keyprefix='01j')
Error Returned: Disjunctions not supported
ORDER BY
Example Query: SELECT EntityDefinition.DeveloperName, ValidationName, Active, Description, ErrorDisplayField, ErrorMessage FROM ValidationRule ORDER BY EntityDefinition.DeveloperName ASC, ValidationName ASC
Error Returned: ERROR: relation "core.virtual_standard_entity_data_template" does not exist
You can always order by fields of the object that you’re querying, but you can get an error when you order by the fields of a joined object.
INCLUDES
Example Query: SELECT ComplianceGroup FROM FieldDefinition WHERE EntityDefinitionId = 'Account' AND ComplianceGroup includes('GDPR')
Error Returned: Unsupported filter type

MetadataComponentDependency (Pilot) doesn’t support GROUP BY or aggregate functions other than COUNT().