36.44. sql_features
  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 36.42. 
    
     sql_features
    
    Columns
   
  
| Name | Data Type | Description | 
|---|---|---|
| 
        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 |