Comment by phailhaus

4 years ago

    SELECT id, name, author

Quick, what is this query about? What's ironic is that I think you have it backwards: the columns are the implementation detail, not the table. The table is the context: you can't change that without having to change everything else. But columns are the last step, the selection after the filters, joins, etc. They can be changed at any time without affecting the logic.

10 comments

phailhaus

taeric 4 years ago

This is... An odd choice. I'd assume I'm not without context looking at a query to know why I would want those columns.

And the auto complete story is backwards. Often I know what columns I want, but I'm not clear what table I need to get them from. Such that, if you make a smarter suggest in the from to only include tables that have the columns, I'd be much happier.

sanderjd 4 years ago
Just throwing in another point of anecdata onto this pile: "Often I know what columns I want, but I'm not clear what table I need to get them from" does not make sense to me. I don't relate at all to their being a global namespace of columns, rather than a namespace of tables, each with its own columns specific to its context.
- taeric 4 years ago
  
  I challenge this. I accept that there are ambiguities, but I assert that you can go really fast by just telling someone to fetch a few columns by name.
  I further assert that if your database is filled with "Id" and "name" columns, instead of "department_name" and similar, you are probably as likely to mess up a join as any benefit you get from the name being short. (And really, what advantage is there in short names nowadays?)
  That all said. I worded my take too strongly. My point should have been that auto suggest should not be confined in either direction.
  
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BeefWellington 4 years ago

It's query asking for the id, name, and author fields. Very straightforward, I have no idea how this is confusing.

> The table is the context: you can't change that without having to change everything else.

Except even in the provided single-table example this isn't true - you're getting subselected/CTEd results. No functional joins are demonstrated unfortunately.

For example:

   from employees
   left_join positions [id=employee_id]

   ...is equivalent to...

   SELECT * FROM employees LEFT JOIN positions ON id = employee_id

No data is selected from positions in either example, and it's unclear on why we're joining that table (other than just for the heck of it). It's not a workable example.

phailhaus 4 years ago
You restated the query; I was asking what it's about. Is it a query across publications? Or is it a query over news articles? That context changes everything: how the query is written, what it can be joined with, how it can be filtered, how it is used, etc. Putting the FROM clause first means that you immediately have context to understand the rest of the query.
- BeefWellington 4 years ago
  
  We can both play this game though:
  FROM articles
  What fields am I expecting in the resultset? Sure I have some context, I know it'll be about articles, but I have no idea what actual data I care about.
  You're arguing that:
  FROM articles SELECT id, name, author
  Is substantially superior to:
  SELECT id, name, author FROM articles
  I don't see them as markedly different with such a small example. HOWEVER, where the difference comes in is the "at a glance what am I getting in my resultset" data that is much easier to see in the latter, second easiest in the former, and not at all present in the linked article.
  I think what this boils down to is what you (any reader, not you specifically) individually expect to need knowledge of when you're writing SQL. In most cases when sitting down to write a brand new piece of code to pull some data from the database, putting the list of tables involved in the query first matters most to some, whereas putting the list of fields to expect in the resultset matters most to others (I put myself in this camp).
  For what it's worth, as I've stated elsewhere while I don't prefer it and would find it annoying to debug personally, I do recognize that the idea of SQL that allows you to list FROM / JOIN / etc. first is very appealing to some. What I think is completely off is the near-obfuscation of the examples in the linked article.
  
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