Pipe Syntax in SQL

>>legran+(OP)
Here is one example from the PDF:

    FROM r JOIN s USING (id)
    |> WHERE r.c < 15
    |> AGGREGATE sum(r.e) AS s GROUP BY r.d
    |> WHERE s > 3
    |> ORDER BY d
    |> SELECT d, s, rank() OVER (order by d)

Can we call this SQL anymore after this? This re-ordering of things has been done by others too, like PRQL, but they didn't call it SQL. I do think it makes things more readable.

>>Cianti+06
The multiple uses of WHERE with different meanings is problematic for me. The second WHERE, filtering an aggregate, would be HAVING in standard SQL.

Not sure if this is an attempt to simplify things or an oversight, but favoring convenience (no need to remember multiple keywords) over explicitness (but the keywords have different meanings) tends to cause problems, in my observation.

>>andy80+D7
You can always turn a HAVING in SQL into a WHERE by wrapping the SELECT that has the GROUP BY in another SELECT that has the WHERE that would have been the HAVING if you hadn't bothered.

You don't need a |> operator to make this possible. Your point is that there is a reason that SQL didn't just allow two WHERE clauses, one before and one after GROUP BY: to make it clearer syntactically.

Whereas the sort of proposal made by TFA is that if you think of the query as a sequence of steps to execute then you don't need the WHERE vs. HAVING clue because you can see whether a WHERE comes before or after GROUP BY in some query.

But the whole point of SQL is to _not have to_ think of how the query is to be implemented. Which I think brings us back to: it's better to have HAVING. But it's true also that it's better to allow arbitrary ordering of some clauses: there is no reason that FROM/JOIN, SELECT, ORDER BY / LIMIT have to be in the order that they are -- only WHERE vs. GROUP BY ordering matters, and _only_ if you insist on using WHERE for pre- and post-GROUP BY, but if you don't then all clauses can come in any order you like (though all table sources should come together, IMO).

So all in all I agree with you: keep HAVING.

zlacker