Discussion [postgres]: ideal way to format SELECT/PERFORM statements with a single column?

[joelmukuthu]

This may not be a bug necessarily, but this:

SELECT some_function_name(
  arg => 1
);

Gets transformed to:

SELECT
  some_function_name(arg => 1);

Whereas I'd expect:

SELECT some_function_name(arg => 1);
-- OR:
SELECT some_function_name(
  arg => 1
);

I understand why this happens but perhaps the plugin could pre-check if converting to hanging indent is necessary. Some other examples:

-- this one makes sense:
SELECT
  loooooooooooooooooooooooooooooooooooooooooooooooooooooooooong_function_name();

-- here perhaps the hanging indent could be removed: 
SELECT
  some_function_name(
    foo => 1,
    bar => 2,
    bar => 2,
    bar => 2,
    bar => 2,
    bar => 2,
    bar => 2
  );

Worth noting that for functions with no params, there's no hanging indent:

SELECT some_function_name();

[nene]

Thanks for reporting. But this is currently somewhat by-design.

The formatter tries to take hints from the original style of the code. Like, it sees that the following SELECT is formatted on multiple lines:

SELECT some_function_name(
  arg => 1
);

so it also adopts the style of formatting it on multiple lines. But the only multi-line style it knows of, is the following:

SELECT
  some_function_name(arg => 1);

One possible improvement is to implement a special style for SELECT followed by a single column.

In any case, it goes more to the category of "what would be the best way to indent this code" rather than "the formatter makes a mistake in here". Which is not to say, it's not an important point to discuss. But it's definitely not a bug.

[joelmukuthu]

Thanks for responding. Thanks for explaining why it happens; I follow your reasoning that this is not a bug.

One possible improvement is to implement a special style for SELECT followed by a single column.

I think that works. Let me know if you'd like help working on this (and #74 as well), in which case I'd need a little help getting pointed in the right direction :)

[nene]

Well, you can look at the current implementation for formatting select_clause:

prettier-plugin-sql-cst/src/syntax/select.ts

Line 65 in ed43c5e

select_clause: (print, node, path, opts) =>

You can play around with it and see what happens. Like when you remove this line:

containsNewline(node, opts) ? breakParent : []

you'll kinda get the behavior you want. But it'll break the other formatting logic. What we likely want to do is something like:

hasMoreThanOneColumn(node.columns) && containsNewline(node, opts) ? breakParent : []