adding SQL feature support matrix

[sploiselle]

This change is

[RaduBerinde]

Review status: 0 of 2 files reviewed at latest revision, 1 unresolved discussion.

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sql-feature-support.md, line 60 [r1] (raw file):

| Component | Supported | Type | Details |
|-----------|-----------|------|---------|
| `INNER JOIN` | ✓ | Standard | [`JOIN` blog post](https://www.cockroachlabs.com/blog/cockroachdbs-first-join/) |

Given our current implementation, we should mark these with a footnote instead of a full "check". The footnote can say that these operations are supported only for small data sets. @knz what do you think?

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Comments from Reviewable

[knz]

Review status: 0 of 2 files reviewed at latest revision, 1 unresolved discussion.

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sql-feature-support.md, line 60 [r1] (raw file):

Previously, RaduBerinde wrote…

Given our current implementation, we should mark these with a footnote instead of a full "check". The footnote can say that these operations are supported only for small data sets. @knz what do you think?

Yes I agree with you. Let's make it a yellow checkmark or a round blue info icon. At least avoid green.

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Comments from Reviewable

[sploiselle]

Review status: 0 of 2 files reviewed at latest revision, 1 unresolved discussion.

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sql-feature-support.md, line 60 [r1] (raw file):

Previously, knz (kena) wrote…

Yes I agree with you. Let's make it a yellow checkmark or a round blue info icon. At least avoid green.

Done. Moved this to the **Statements** section since all of the `JOIN` types are supported and had the same info and lengthy note. Avoided obfuscating the info by changing the "Supported" column from ✓ to Functional, with the specification about small data sets in the "Details" column.

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Comments from Reviewable

[RaduBerinde]

Very nice, thank you!

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Review status: 0 of 2 files reviewed at latest revision, 1 unresolved discussion.

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Comments from Reviewable

[jseldess]

Excellent work, @sploiselle! LGTM.

@nvanbenschoten, should introspection be added? If so, can you suggest an approach?

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Reviewed 2 of 2 files at r1.
Review status: 1 of 2 files reviewed at latest revision, 3 unresolved discussions.

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sql-feature-support.md, line 7 [r1] (raw file):

## Overview
Making CockroachDB easy to use was a top priority for us, so we chose to implement SQL. However, even though SQL has a standard, no database implements all of it, nor do any of them have standard implementations of all features.

Let's continue this priority until the end of time: "...easy to use is a top priority for us..."

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sql-feature-support.md, line 11 [r1] (raw file):

To understand which standard SQL features we support (as well as common extensions to the standard), use the table below.

- __Component__ lists the components that are commonly considered part of SQL.

nit: Would you mind using **Component** as the markdown for bold, for consistency with other pages?

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Comments from Reviewable

[nvb]

@jseldess We could add a section for supported methods of introspection, but I foresee a page/section like https://www.postgresql.org/docs/9.5/static/information-schema.html being more immediately useful. Each subsection would provide a brief overview of a supported introspection table, along with it's schema.

[jseldess]

Thanks, @nvanbenschoten. Noted.