mongodb sql-comparison

http://docs.mongodb.org/manual/reference/sql-comparison/

databasedatabasetablecollectionrowdocument or BSON documentcolumnfieldindexindextable joinsembedded documents and linking 

primary key

Specify any unique column or column combination as primary key.

primary key

In MongoDB, the primary key is automatically set to the_id field.

aggregation (e.g. group by)

aggregation pipeline

See the SQL to Aggregation Mapping Chart.