Add docs for SRF column accessors

[rmloveland]

Fixes #3070

[cockroach-teamcity]

This change is 

[cockroach-teamcity]

http://cockroach-docs-review.s3-website-us-east-1.amazonaws.com/941128ce8940cfe27c3f90de9d2d72a2be4c1f29/

[rmloveland]

Specific change is in the Table generator functions section.

[cockroach-teamcity]

http://cockroach-docs-review.s3-website-us-east-1.amazonaws.com/eee416f2223e054845f24bee806ad6926d8c6432/

[rmloveland]

@jseldess mind giving this one a look again? thanks!

[knz]

thank you

[jseldess]

LGTM, with a few questions.

Reviewable status: complete! 0 of 0 LGTMs obtained

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v2.1/table-expressions.md, line 189 at r2 (raw file):

{% include copy-clipboard.html %}
~~~ sql
> SELECT * FROM generate_series(1, 3)

While you're here, would you mind adding a semicolon here so this can be pasted and run directly in the shell?

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v2.1/table-expressions.md, line 203 at r2 (raw file):

<span class="version-tag">New in v2.1:</span> Set-returning functions (SRFs) can now be accessed using `(SRF).x` where `x` is either:

- The name of a column returned from the function, or

nit: This isn't in our style guide, so it's up for debate, but I prefer to keep conjunctions out of bulleted lists. So I'd either introduce it a little differently (e.g., where x is either of the following:) or just integrate into the sentence (e.g., where x is either the name of a column... or ...).

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v2.1/table-expressions.md, line 214 at r2 (raw file):

~~~
 x | n

Should the above statement produce this output for me? I'm getting:

root@127.0.0.1:63810/defaultdb> SELECT (i.keys).* FROM (SELECT information_schema._pg_expandarray(indkey) AS keys FROM pg_index) AS i;
  x | n
+---+---+
(0 rows)

Time: 2.935ms

[jseldess]

Oh, also, is this PR fixing an issue? If so, can you use Fixes #<issue> or the like?

[rmloveland]

Thanks @jseldess!

Reviewable status: complete! 0 of 0 LGTMs obtained

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v2.1/table-expressions.md, line 189 at r2 (raw file):

Previously, jseldess (Jesse Seldess) wrote…

While you're here, would you mind adding a semicolon here so this can be pasted and run directly in the shell?

Fixed - thanks!

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v2.1/table-expressions.md, line 203 at r2 (raw file):

Previously, jseldess (Jesse Seldess) wrote…

nit: This isn't in our style guide, so it's up for debate, but I prefer to keep conjunctions out of bulleted lists. So I'd either introduce it a little differently (e.g., where x is either of the following:) or just integrate into the sentence (e.g., where x is either the name of a column... or ...).

Fixed. Went with the "where x is one of the following: ..." formulation.

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v2.1/table-expressions.md, line 214 at r2 (raw file):

Previously, jseldess (Jesse Seldess) wrote…

Should the above statement produce this output for me? I'm getting:

root@127.0.0.1:63810/defaultdb> SELECT (i.keys).* FROM (SELECT information_schema._pg_expandarray(indkey) AS keys FROM pg_index) AS i;
  x | n
+---+---+
(0 rows)

Time: 2.935ms

AFAICT the output varies depending on the contents of the current database. I think this is because information_schema is used for name lookups by IDEs and things.

Fixed by updating to add "For example (note that the output of queries against information_schema will vary per database):" to be (hopefully) clearer.

[cockroach-teamcity]

http://cockroach-docs-review.s3-website-us-east-1.amazonaws.com/9f55e1c8d657e9d0b598f632c91e1431ffd1053c/