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Comment by no_protocol | Hacker News Reader

I have often seen commas placed at the start of each line when columns are being listed. I'm a little surprised this guide doesn't follow that convention. It would fit nicely with the established pattern of lining everything up:

  SELECT first_name
       , last_name
       , email_address
    FROM users

Can anyone speculate why it's not done this way in the guide? I think the reasoning behind it was to make later modification easier because adding or removing the last field required modifying two lines.

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This is a pretty commonly asked question. The answer is two fold:

1. putting the comma before doesn't actually make commenting out columns easier - it just moves the problem to the other end of the list. Just try commenting out `first_name` in your example and you'll see what I mean.

2. because normal convention would be for the comma to come immediately after an item in written English.

Re; #1, I also use comma-first indenting and I actually put each field in it's own line specifically for ease in commenting (first_name would have its own line)

This doesn't solve the problem at hand either unfortunately. You'll still have a hanging comma in front of `last_name`:

  SELECT 
      -- first_name
       , last_name
       , email_address
    FROM users

When parsed it will look like this query error to the system:

  SELECT
       , last_name
       , email_address
    FROM users

I'm surprised too. I'm unaware of any disadvantages to doing it this way. I have always preferred this format myself. It makes things easier to comment out, it makes it so the clause never accidentally ends in a trailing comma before the next clause, and it looks nice.

I just think it looks visually ugly. I've heard others think that too, so it's not just me. I don't feel like the problem it solves is really that big of a deal. I can always just clone the second line up since order normally doesn't matter.

Yeah, basically it's a good practice to start field name rows with commas as it makes it quicker to comment them out as you're tweaking the SQL code (though there's no harm in putting multiple fields on a single row, especially if they come from related tables).

Besides the first reason pointed out by Treffynnon, it's worth remembering that the code we write is primarily for our fellow humans and that a piece of code will most likely be read more times than written so we better strive to optimize it for legibility.

I'm a little surprised that anybody follows the "commas at the beginning of the line" convention - but to each their own.

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