Hello Andrew, Thursday, November 12, 2020, 3:19:39 PM, you wrote:
> On 11/11/20 7:55 PM, Bruce Momjian wrote: >> On Thu, Nov 12, 2020 at 12:18:49AM +0000, Dagfinn Ilmari Mannsåker wrote: >>> Bruce Momjian <br...@momjian.us> writes: >>>> I think we could do it, but it would only work if the column was output >>>> as a single json value, and not a multi-key/value field. I am afraid if >>>> we tried to do it, the result would be too inconsistent to be useful. >>> Could this be done via the support function, so that the top-level >>> operator/function in each select list item can return a suggested column >>> name if the relevant arguments are constants? >> Yes, the user explicitly calling a function would be much easier to >> predict. >> > I suspect this is doomed to failure. There is no guarantee that the path > expression is going to be static or constant across rows. Say you have > this table: > x: foo, j: {"foo": 1, "bar": 2} > x: bar j: {"foo": 3, "bar": 4} > and you say: > select j->>x from mytable; > What should the column be named? Suppose it should be named 'as x' > I think we'd be trying to manage a set of corner cases, and all because > someone didn't want to put "as foo" in their query. And if we generate a > column name in some cases and not in others there will be complaints of > inconsistency. > cheers > andrew > -- > Andrew Dunstan > EDB: https://www.enterprisedb.com -- Best regards, Eugen Konkov