Here is a simple example of how to query a CSV file. We will go through the complete process of defining the storage, placing the CSV file in the filesystem and querying the file.
Here is an excerpt from the file which is named "airports.csv". It is a list of airports and contains around 46000 records.. The individual fields are delimited by comma. The first row is a header row defining the names of the fields.
Further down - under "formats" - there is the definition for the CSV format. Note that "extension" is set to "csv" - the file extension. Then there is an entry for "skipFirstLine". It is set to "true" because we have a header line in the CSV file, which we want to skip - otherwise drill treats it as a regular line of data. And then there is an entry for "delimiter" which defines how the individual fields are seperated - in this case by a comma.