cataloging prior art: data filtration & selection syntaxes

[b5]

We're starting into research for a selector syntax for Qri, and need to catalog appropriate
potential follow up. If you know of a selection syntax that we haven't mentioned here, please suggest it.

Example Use Cases:

filter

1. Selecting just the title field from a dataset
2. selecting the coordinates field from a deep-nested object that has a type field who's value is equal to Point
3. Selecting the last 4 values of an array
4. Selecting unique, sorted address field from a table
5. Selecting from an array-of-arrays by a given schema column label

join

1. Joining two datasets together on a datestamp column
2. Joining two datasets together by an id field, where the id field is in a different place on either dataset

Syntaxes so far:

• SQL
• Pandas DataFrame
• jq
• xpath
• MongoDB query operators (@Mr0grog's suggestion)
• Graphql