Is your feature request related to a problem? Please describe.
Provide help in CLI for sub-commands

Describe the solution you'd like
Sub-commands help should describe the sub-command's functionality and options available for the sub-command

Describe alternatives you've considered
N/A

Additional context
See: golang-migrate/migrate#370

Steps to reproduce:

1. Create table with some data in Hive:

CREATE TABLE test (v int);

INSERT INTO test VALUES (5),(1),(1),(1),(2),(2),(2),(2),(3),(3),(3),(4),(4),(4),(4),(4),(4),(5),(5),(5),(5),(6),(6),(6),(6);

2. Select test table and choose v column.
   ![Zrzut ekranu 2019-07-9 o 14 36 11](https://user-images.githubusercontent.com/3193882/60888678-b25ffb80-a257-11e9-8c88

2019/12/02 和Yi Wang沟通交流考虑SQLFLOW可以支持如下的特性

一、基础功能：好用的工具需要一个更加简易友好的界面，让业务开发/分析更加简单
1)设计分析类工具，提供自动联想输入、快速语法、常见语义错误，提升用户体验
应用场景：提供IDE的自动联想功能，提高开发效率；语法和基本语义提前检查，避免提交到后台，执行较长时间后报错
2)大数据量时时间较长，建议提供任务(job)管理、允许用户了解数据执行的状态、监控进度、提供动态调试、watch能力，方便用户感知和调优
应用场景：耗时任务可以快速了解整体进度，提供一些中间的过程信息、耗时等，方便用户进行调优,优化开发
3) 安全权限、用户管理、
应用场景：增加新的数据分析人员、用户权

I don't know what the plans are for this software, but if there is a reasonable chance that it will require bug fixes or new features in the future, I would recommend that someone experienced with the system spend maybe 1-3 hours on basic developer documentation - just enough to orient a new person to the code.

If no more work will ever be done, this issue is moot and should be closed as a 'won

Add the ability to provide a custom document id (aka key) to set using a new command specific option --key. This feature also bumps the major version to 2.0.0.

Requires updating README.md, CHANGELOG.md, and adding new specific tests for this case as well.

The MIN aggregator in Virtuoso seems to skip unbound values, at least in the example below, and I think that's wrong.

insert data {
  <http://s1> <http://p1> <http://o1> .
  <http://o1> <http://p2> <http://o2> .
  <http://x> <http://p1> <http://y> .
}

select (min(?o2) as ?min) {
  ?s <http://p1> ?o1 .
  optional { ?o1 <http://p2> ?o2 }
}

This returns <http://o2> corresp

We use EBS Volume snapshots for our mongodb backup. It would be nice if this tool allows us to call AWS CLI to kick off ebs volume snapshots

To test the fix in #222, we should create a unit test that runs IMPORT FOREIGN SCHEMA on a schema that contains no tables.

Hi, I wanted to know is there support for multiple datasource in hera and if so, how can we mention it using the TWO_TASKS parameter as presently it is accepting only one connection detail as mentioned in the page.. There is option to mention different shards but if we want connectivity to different databases, how to do t

As an Architect, I would like to control the database version control and automatic migration, so that the DevOps team has no database migration headaches besides preventing the database from corruption.

Add support to Product & Recommendation services database to use Mongock for ease of database versioning.