   Attention: the data frames do not match exactly, but as no primary key columns are
   provided, the row and column matches cannot be computed.

 Schemas
 ▔▔▔▔▔▔▔
   ┏━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┓
   ┃  In common   ┃  Right only  ┃
   ┃   1 column   ┃  2 columns   ┃
   ┡━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━┩
   │     ...      │ col_a [Null] │
   │              │ col_b [Null] │
   └──────────────┴──────────────┘
