5. SQL Query

For times when very basic data inspection is required, the query command can be useful. It allows SQL like queries directly on your data sources. For instance, if we interested in the number of sales and number of unique purchases over a 10 day span from our woodworking data, we can execute:

$ ess query "select count(distinct userID) FROM purchase:2014-09-01:2014-09-10"
"row","k_userID"
13618,4929

Be sure to run this AFTER defining the datastore from the earlier tutorial. We can filter using the WHERE clause:

$ ess query "select count(*) FROM purchase:2014-09-01:2014-09-10 WHERE articleID >20"
"row"
7818

This is much simpler than loading data into a database or other system and obtaining the result. The price for this convenience is that the query command does not support many SQL keywords. A future update will expand the functionality of this interface.