Question: Best way to rename columns? about hugsql HOT 8 CLOSED

This can be achieved a couple of ways with either Clojure Expressions or implementing your own HugSQL parameter type.

Here's the general idea with a Clojure Expression:
SQL

-- :name select-labeled-identifiers :? :*
/* :require [clojure.string :as string]
            [hugsql.parameters :refer [identifier-param-quote]] */
select
/*~
(string/join ", "
  (for [[field label] (:cols params)]
    (str (identifier-param-quote field options)
      (when label (str " as " label)))))
~*/
from test

Clojure:

(testing "labeled identifiers: col_name as label_name"
    (is (= ["select  a as lbl_a, b as lbl_b, c from test"]
           (select-labeled-identifiers-sqlvec
            {:cols [["a" "lbl_a"]
                    ["b" "lbl_b"]
                    ["c"]]}))))

If you're going to use this kind of thing very often, then implementing a custom HugSQL parameter type is probably worth it.

I'm might consider adding a couple of built-in parameter types to support this pattern (:aliased-identifier and :aliased-identifier-list). Let me think on that.

from hugsql.

Here's a different way to do it. This expression does not require the use of identifier-param-quote, but instead rewrites the parameters to use identifier param types referenced by the index in the passed-in vector using HugSQL's Deep Get Param Name feature. And, I put it in a snippet named cols for reuse:

-- :snip cols
/* :require [clojure.string :as string] */
/*~
(string/join ", "
  (map-indexed
    (fn [i [field label]]
      (str ":i:cols." i ".0" 
        (when label (str " as :i:cols." i ".1"))))
    (:cols params)))
~*/

-- :name select-labeled-identifiers :? :*
select :snip:cols from test

Only issue here is that calling the snippet is a little verbose with the cols

(testing "labeled identifiers: col_name as label_name"
    (is (= ["select a as lbl_a, b as lbl_b, c from test"]
           (select-labeled-identifiers-sqlvec
            {:cols (cols {:cols [["a" "lbl_a"]
                                 ["b" "lbl_b"]
                                 ["c"]]})}))))

from hugsql.

So, I decided the best way to tackle this was to just extend the existing identifier parameter types to support aliases. This will be in the next release allowing you to pass along vector pairs:

 (is (= ["select id as my_id, name as my_name from test"]
           (identifier-param-list-sqlvec {:columns [["id" "my_id"], ["name" "my_name"]]})))
    (is (= ["select * from test as my_test"]
           (identifier-param-sqlvec {:table-name {"test" "my_test"}})))

from hugsql.

Thanks for all your help. Really enjoying hugsql so far!

from hugsql.

This is released in 0.4.6. Give it a try!

from hugsql.

Just curious, is there a reason why :table-name uses map notation whereas :columns uses array notation?

from hugsql.

Well, you can actually use either, but I copied examples from the test suite here that didn't match. The docs use vectors in both cases and that is the preferred usage: http://www.hugsql.org/#param-identifier

from hugsql.

That reminds me...the test suite should not assume column order when using a map.

from hugsql.