3.6 Summary

Here is a table of key SQL clauses in order:

Clause	Description	Required
SELECT	Columns or expressions to be returned	Yes
FROM	Table from which to retrieve data	Only if selecting data from a table
WHERE	Row-level filtering	No
GROUP BY	Group specification	Only if calculating aggregates by group
HAVING	Group-level filter	No
ORDER BY	Output sort order	No

SQL for various data science languages

• SQL for R (You should really learn dplyr……the package here is just FYI)
  • SQLDF Package
  • Documentation
  • Examples
• SQL for Spark
  • Documentation
• SQL with Hadoop
  • Hive Overview
  • Documentation
• SQL for Python
  • Python-SQL Package Documentation