Joining 

Aggregation

Merging

Grouping

Schema

Table

Column

Row

Tables

Rows and columns

Documents

Key-value pairs

5432

27017

3306

22

Row

Index

Table

Column

Shard

Index

ObjectId

Replica Set

Cassandra

All of the above

MongoDB

DynamoDB

CREATE PROC proc_name() AS && SELECT * FROM table_name;$$

CREATE FUNCTION func_name() RETURNS VOID AS  LANGUAGE plpgsql;

CREATE PROCEDURE proc_name AS SELECT * FROM table_name; 

CREATE FUNCTION func_name() RETURNS VOID AS  LANGUAGE plpgsql;

Stored procedures run and used for managing administrative activities of SQL Server 

Stored procedures that can return a single value or a set of rows

Stored procedures that can be written in any language supported by the .NET Framework 

Stored procedures that allow you to loop through a SQL statement's result