The table sql_features contains information about which formal features defined in the SQL standard are supported by PostgreSQL. This is the same information that is presented in Appendix D. There you can also find some additional background information.
Table 34-41. sql_features Columns
|feature_id||character_data||Identifier string of the feature|
|feature_name||character_data||Descriptive name of the feature|
|sub_feature_id||character_data||Identifier string of the subfeature, or a zero-length string if not a subfeature|
|sub_feature_name||character_data||Descriptive name of the subfeature, or a zero-length string if not a subfeature|
|is_supported||yes_or_no||YES if the feature is fully supported by the current version of PostgreSQL, NO if not|
|is_verified_by||character_data||Always null, since the PostgreSQL development group does not perform formal testing of feature conformance|
|comments||character_data||Possibly a comment about the supported status of the feature|
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