diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/clojure_sql/dsl.clj | 41 |
1 files changed, 22 insertions, 19 deletions
diff --git a/src/clojure_sql/dsl.clj b/src/clojure_sql/dsl.clj index e33bbfb..8e4a24d 100644 --- a/src/clojure_sql/dsl.clj +++ b/src/clojure_sql/dsl.clj @@ -268,6 +268,14 @@ quote can be used to suppress evaluation of terms in the expression. + If the query being filtered is the result of a previous grouping + operation then a `select` operation will compile in one of two + different ways: + 1. If the selection is entirely made on grouped attributes it will + compile into a `having` clause in the resulting query. + 2. If the selection includes non-grouped attributes then a + subquery will be introduced. + Example: (select query `(= :id 10)) - filter for an id of 10 (select query {:id 10}) - equivalent to the above @@ -275,9 +283,20 @@ [query expression] (let [expression (if (map? expression) (reduce combine-conjunctions - (map #(cons '= %) expression))) - resolved-expression (process-expression (:tables query) (:fields query) expression)] - (update-in query [:where] combine-conjunctions resolved-expression))) + (map #(cons '= %) expression)) + expression) + expression-fields (filter keyword? (flatten expression)) + bad-expression-fields (set/difference (set (process-expression nil + (:fields query) + expression-fields)) + (set (:group query))) + where? (nil? (:group query)) + having? (empty? bad-expression-fields)] + (if (or where? having?) + (let [attr (if where? :where :having) + resolved-expression (process-expression (:tables query) (:fields query) expression)] + (update-in query [attr] combine-conjunctions resolved-expression)) + (recur (convert-to-subquery query) expression)))) (defn sort "Apply a sort to a query. Replaces any existing sort on the @@ -320,22 +339,6 @@ (assoc query :group (map (partial resolve-field (:tables query) (:fields query)) fields-seq)))) -(defn having - "Apply a filter to the groupings of a query. - - `expression` is the same as a `select`, but may only reference - fields by which the query is grouped (see `group`) or other fields - within aggregating functions (eg. count). - - Example: - (having query `(< (sum :age) 100)) - select groups with a combined - age under 100" - [query expression] - (let [old-having (:having query) - resolved-expression (process-expression (:tables query) (:fields query) expression) - new-having (combine-conjunctions old-having resolved-expression)] - (assoc query :having new-having))) - (defn take "Limit the number of results of a query. |