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A neat trick on writing sql that I learned working with Oracle consultants: SELECT field1 , field2 , field3 , another_field FROM ... By pl

• ebbv 14y ago
  No, no, no. Comma first variable listing is the worst thing ever in the history of the world. Having the comma in the proper place has such a negligible cost (oh no I might have to delete the comma on the last element and add it to the formerly-last element!), and having it like this looks so god awful and doesn't really save you anything if you're swapping the first element instead of the last one.
  • hdctambien 14y ago
    Why is "after the element" the proper place for a comma?
    • noblethrasher 14y ago
      It's probably more pleasent and easier to read for the next person.
    • rtfeldman 14y ago
      That's where it goes in English.
    • jkeel 14y ago
      That's what I was wondering. The comma is just a separator. Plus it's only really needed BEFORE each field not after the preceding field.
    • hdctambien 14y ago
      (I can't reply to my reply) Comma first seems more consistent to me.... unless you write your WHERE clauses like this: WHERE a=b AND a=d AND e=f
    • ebbv 14y ago
      The same reason that you should put spaces before and after your logical operators. The same reason you should use consistent spacing on the left and right parenthesis. The same reason you should use caps for the SQL and lower case for all table and field names. Because it makes your SQL more legible. In english, commas go after the previous word, not before the next word. The syntax is the same for all programming languages. The fact that most compilers and interpreters don't require it is not an excuse for abusing it.
      • cptskippy 14y ago
        I disagree with you regarding legibility. I've been using commas like this in SQL for 10 years and I find it to be much more legible and functional this way. Besides the subjective argument of legibility, what other benefits does it have? Having a comma preceding something is an indicator that it is one of many. When debugging you can easily comment out the column, or table from a query.
        • ebbv 14y ago
          Again, you can comment out lines with the normal syntax too. There's no reason for this gimmick syntax. In theory it makes the last 2 elements easier to deal with but it makes the first two harder. It's silly, and it's ugly.
      • dennisgorelik 14y ago
        Lowercase for table names? I think table names should be in PascalCase. And I personally prefer the rest of SQL to be in lowercase, so it does not attract too much attention. Usually in SQL table names and column names is the most important information.
  • unoti 14y ago
    The sensibilities for everything you just said are entirely subjective, and change as you are exposed to them. If you spend all day every day writing SQL, it is different than if you do it a little here and there. The entire codebase of Oracle Apps looks like this, so I found I grew accustomed to it over time and saw the benefits. Editing commas actually can be significant in terms of time and drag (this is even more apparent when edit Erlang). Being very dogmatic, and in a discussion of ideas saying "that's the worst thing in the world" is easily worse than comma placement. So surely commas as indentation isn't the worst thing in the world.
    • ebbv 14y ago
      It's not the worst thing in the world. It's the worst thing in the history of the world. Get it right, gosh. Seriously, though, hideous syntax is bad. It makes life miserable for everyone who has to work on your code after you. Don't do it, no matter what good reasons you think you have.
      • rosser 14y ago
        "Ugly" is a subjective judgement. "Worst thing in the history of the world" is a subjective judgement, and egregious hyperbole, to boot. Saying that mitigates pretty much all the credibility of any rational, non-hyperbolic argument you might also have offered in support of your point. I find having to re-run my query because I forgot to delete the comma following the penultimate item in the SELECT list when I commented the ultimate one out "ugly". Additionally, everyone I have ever explained this concept to has said some variation of, "Wow, that's a great idea. Thanks!" No one has ever said, "That's the worst thing in the history of the world" ... until you. I've been doing database work professionally for a decade now. I've explained this concept to a lot of people.
        • ebbv 14y ago
          Chances are if you're explaining this to someone they have less experience than you so they wouldn't be in a position to tell you that this is a bad practice. Like I said, objectively, you're just moving the extra work from moving around the last element to moving around the first element. You're not really saving any time. Plus even if you accept the argument that you are saving time (pretend you live in a world where you never move the first element) the time you save is negligible. If you hadn't resorted to this ugly syntax, you should have developed habits that lead you to fix your commas whenever you move the last element around. Obviously you can do what you want, but if you were on my team, I would not allow this syntax.
  • jradakov 14y ago
    I don't like having comma first listings, but it makes it incredibly easy to comment out parts of a query. I find commenting out parts of a query essential when trying to debug really long, complex queries.
  • btilly 14y ago
    My experience. Changed formatting is a shock the first time. But it does not take long to retrain yourself to find it aesthetically more pleasing. When you're making a quick fix to a batch job that does not hit the problematic query for 30 minutes, the cost of messing up the comma is 30 minutes. (Yeah, I know, it all should be properly factored out, and unit tested. But there is a lot of lightly tested code in the real world that behaves just like I said.) Because SQL is stored as plain text, there is real value in making your mental compiler have to do no work to notice stupid syntactical stuff.
    • ebbv 14y ago
      That's a methodology problem you're describing. The solution should not be hideous syntax.
      • btilly 14y ago
        There are a ton of companies out there doing interesting things that are willing to pay well for working on code that has that methodology problem. But they are not willing to undertake a full rewrite of their system at the outset before you can start doing anything useful. At that point you can choose which is more important - the religious war or getting on with your life. When I encounter things like that my vote is a bit of both. I bring habits that allow me to cope with the methodological problem, and incrementally try to create a space where I don't have a problem. In the process I've found that my preference for trailing commas was a useless idiosyncrasy that I could live without. When I tried living without it, I quickly found that leading commas made my life more pleasant, and I learned to like that formatting style.
    • garblegarble 14y ago
      Couldn't you use an IDE that understands SQL? IntelliJ does this - it recognises the SQL dialect you're using and can even validate against the tables & columns in your schema
      • btilly 14y ago
        Discussing IDEs is a different religious war. Outside of the Java world, people are not so wedded to IDEs. Going back to my last job that was mostly SQL, I was working in Perl, with SQL embedded in TT templates. Good luck finding an IDE that understands that. In that job the comma placement was critical. Which column would be the last column would depend on what options the report was being generated with. The point is that people would ask for many variations on the same report. One person would want a top level view, another would want to break out event type, another would want to break it out by which type of advertising campaign was thrown at it - and all were being generated out of the same templated SQL so I didn't have to maintain code in parallel. But the result is that in the code I couldn't make assumptions about which column was going to wind up being last. Thanks to leading comma formatting, it was sufficient to require that the FIRST field stayed the same. Which proved to never be a problem.
  • mmsimanga 14y ago
    Not sure why the strenuous objection to the comma first. I too code that way and a couple of SQL formatting tools such as http://poorsql.com/ http://poorsql.com/ have the comma first as the default setting. An added advantage to the one mentioned by the original comment is being able to utilise column editing features.
• iaskwhy 14y ago
  For the WHERE clauses one can use: WHERE 1=1 AND ... --AND ... AND ... I do not like having commas at the beginning of the lines though.
  • ExpiredLink 14y ago
    > WHERE 1=1 ORM frameworks frequently use this when they create SQL.
• ajw0100 14y ago
  Along the same lines it makes it easier to comment out items when debugging. Especially if you add in tricks like SELECT 0. For example multiple lines in this query would cause an error: SELECT a.field1, a.field2, -- b.field1, -- b.field2, c.field1, -- b.field3 FROM a, -- b, c WHERE --a.field1 = b.field1 AND a.field2 = c.field1 This query would not cause an error (Note that DUAL is a dummy table in Oracle that contains 1 column and row): SELECT 0 , a.field1 , a.field2 --, b.field1 --, b.field2 , c.field1 --, b.field3 FROM dual , a --, b , c WHERE 0=0 -- AND a.field1 = b.field1 AND a.field2 = c.field1 It does add a 0 column to the result set but that can be dealt with or removed after development.
• MartinCron 14y ago
  This reminds me about something that I like in C#, you can leave an extra comma at the end of a sequence and the compiler doesn't freak out on you.
  • ajw0100 14y ago
    Python is the same way - it lets you have trailing commas for lists, tuples, and dictionaries.
  • btilly 14y ago
    JavaScript is almost the same way. It works in some browsers, but not in others. :-(
    • Osiris 14y ago
      This exact issue caused us to deploy code that completely broke our application in IE7. There was a trailing comma in a list which all browsers ignore except IE6/7. To this day we still give that dev (the team lead) a hard time about the trailing comma. We since implemented mandatory linting on all JS.
  • genwin 14y ago
    So often I've wished SQL worked like that. Go requires a comma at the end of a sequence.
• aidos 14y ago
  I do something similar: select site.name , site.plan , site.status , domain.domain , subscription.updated_at from subscription inner join site on subscription.site_id = site.id inner join domain on domain.site_id = site.id where subscription.status = 'inactive' and subscription.plan = 'pro' and domain.created_at <= '2012-04-01' order by subscription.updated_at desc When I was writing a lot of sql I found it a lot easier to work with (when you're commenting things out a lot during development for example). Also, I'm a geek, so I like stuff lined up. I understand the arguments for putting commas at the end of the line. For example, Google say in their style guide that when reading, having the comma at the end alerts the reader to the continuation on the next line. In languages that allow trailing commas (Python, php, C# etc) that's what I do. I put them at the front otherwise. It's certainly not worth an overreaction though. Having commas on either end of the line isn't going to kill anyone. I've written 1000s of lines of sql in both styles and the world hasn't imploded yet. As always, be consistent with the surrounding code - that's more important than any other rules (especially ones with a purely subjective basis).
• saurik 14y ago
  By putting the commas at the beginning, you can easily reorganize the sequence without messing with the commas for all but the first element. By putting the commas at the end, you can easily reorganize the sequence without messing with the commas for all but the final element. I do not see how this is any different. Maybe the description should be more of the form "I can append entries to the end by simply adding a single line"?
• Someone 14y ago
  I do the same in C++: myClass::myClass(int aa,int bb) : a(aa) , b(bb) , p(new int[aa]) , c(17) {} Yes, that looks weird at first, but you get used to it (and, to be honest, everything in C looks weird at first).