Null clause

[infinity-computers-dot-net]

I don't know if anyone's actually maintaining this package anymore, but I looked at the source and can't figure out how to solve it.

The problem here is sometimes I want to use a where or limit clause, and sometimes I don't. So given that select is a macro, how do I selectively include or exclude a clause?

Here's what I tried:

(defun select-from-db (my-limit my-where)
 (select columns
  (from mytable)
  (and my-limit (where my-limit)
  (and my-where (limit my-where)))

The idea being that I can pass nil for these values, and have the clauses omitted. But this doesn't work. The package complains that "you can't have null twice" or some such.

Without duplicating my code four times, how can I selectively include or exclude clauses?

[infinity-computers-dot-net]

For what it's worth, I tried quasi-quote tricks; I tried writing my own macro wrapper around select, and I tried assembling an argument list at runtime. Nothing helped, because select is a macro.

[fukamachi]

I didn't notice this doesn't work while using SxQL with Mito because Mito's select-dao ignores null clauses.
It would be good if SxQL's select macro also works like it.

[Mr-Dispatch]

https://github.com/mmontone/sxql-composer might help in the meantime