Automated Documentation - Phase 3

[dai-chen]

We've already prepared docs for basic usage of plugin and simple SELECT query: https://github.com/opendistro-for-elasticsearch/sql/blob/master/docs/user/index.rst. In this phase, we want to generate more documents for what's left:

1. DQL
   1.1 Complex query: Subquery, JOIN, MINUS/UNION
   1.2 SHOW/DESCRIBE
   1.3 SQL Functions
2. DML
   2.1 DELETE
3. Beyond SQL
   3.1 PartiQL Compatibility
   3.2 Full Text Search
   3.3 Elasticsearch special functions

[dai-chen]

Note that SQL Functions need to be generated from our type system in semantic analyzer. And there are many ES special functions in our codebase. So for these parts, we may only put basic information for now due to time limit.

[dai-chen]

Due to the time limit, docs for SQL functions only list specification for now. More descriptive information will be added in future. As for ES special functions, it takes time to figure out the spec and semantic so skip it for now too.

[anirudha]

👍 thanks