Add basic SELECT concept/exercise

[blackk-foxx]

Incorporates ideas from #217, #218 and #219.

[blackk-foxx]

Are hints needed for this one? I'm open to suggestions...

[IsaacG]

FWIW it's worth noting that this will fail on Mac with the default/older bash.

[glennj]

If you want to write a guard for that:

if (( BASH_VERSINFO[0] < 5 )); then
  echo "get a modern bash from Homebrew" >&2
  exit 1
fi

[glennj]

And jq is not standardly installed:

if ! command -v jq >/dev/null; then
  echo "Required tool 'jq' is not installed" >&2
  exit 1
fi

[blackk-foxx]

I guess it would be nice, for users that want to run the tests locally. But I would recommend against anything Mac-specific like "Homebrew" in the error message.

[IsaacG]

Any Linux system ought to have bash5 😄 I don't think the exact message matters much, thought for Mac users (the primary target of that message) a nudge towards Homebrew could be handy.

[blackk-foxx]

Of course, Windows users would need to do a lot more to run the tests, like install a bash-compatible environment such as cygwin or mingw, and then ensure jq is installed in the environment. Maybe it would make sense to update sqlite/exercises/shared/.docs/tests.md accordingly, as well as adding the guards in the script?

[glennj]

Homebrew is for Linux too. I prefer it for some packages (like exercism) because it usually provides quicker access to new versions.

[blackk-foxx]

And/or instructions for running the tests in Docker?

[glennj]

Since we have installation instructions for Windows, it's a bad look if the first concept exercise can't run on Windows.

I fired up a Windows VM and installed sqlite (via chocolatey: did you want a PR with those instructions?) -- the sqlite3 cli's .shell command uses cmd, so we'd want a batch file equivalent of the shell script.

Anybody want to take that on?

[blackk-foxx]

I might give it a try, if I can spin up a Windows VM somehow without buying a license.

[IsaacG]

@glennj @vaeng Any things/feedback before we merge this?

[glennj]

Some of the pattern matching operators are probably specific to sqlite. Did you want to stay more db-neutral?

[blackk-foxx]

I don't really have a strong opinion here. I guess it would be nice to stay as generic as possible, but the concept docs do provide links to SQLite specific docs.

[IsaacG]

This is the SQLite track, not a generic SQL track. I think SQLite specific things are completely fine, and probably even preferred.

[glennj]

I assume this is the same as the concept introduction document. You might want to use a template. When you make changes to the concept doc, you don't have to make the same changes here but just do bin/configlet generate

[blackk-foxx]

It's close, but not an exact copy:

127a128,132
> 
> In addition to `=` and `BETWEEN...AND`, the `WHERE` clause supports a wide range of expressions, including comparison (`<`, `<=`, `>`, `>=`), pattern matching (`LIKE`, `GLOB`, `REGEXP`, `MATCH`), and checking for membership in a list (`IN`, `NOT IN`).
> See [SQL Language Expressions](sql-expr) for the complete documentation.
> 
> [sql-expr]: https://sqlite.org/lang_expr.html

[glennj]

If you want to write a guard for that:

if (( BASH_VERSINFO[0] < 5 )); then
  echo "get a modern bash from Homebrew" >&2
  exit 1
fi

[glennj]

And jq is not standardly installed:

if ! command -v jq >/dev/null; then
  echo "Required tool 'jq' is not installed" >&2
  exit 1
fi

[glennj]

I was checking it out in Windows, in a git-bash environment:

• had to install jq from jqlang.org
• had to change this line

  mapfile -t slugs < <(jq -r 'keys[]' test_data.json | sed 's/\r$//')

  I suppose the jq build for windows was adding carriage returns 'cuz it's windows. Annoying.
• Then the exemplar ran successfully (after fixing the quoting bug)

I haven't really thought about a powershell translation of the results script though.