gistfile1.clj

(require '[clojure.string :as s])

((fn [{:keys [sql replacements]}]
   (reduce (fn [acc [k v]] (s/replace acc k v)) sql replacements))
 {:sql "select * from schema_name.table_name where table_name.field_name='field_value'"
  :replacements {"schema_name" "production"
                 "table_name"  "employees"
                 "field_name"  "name"
                 "field_value" "nelo"}})
; => "select * from production.employees where employees.name='nelo'"

gistfile2.clj

(require '[clojure.string :as s])

(def sql-replace
  (fn [{:keys [sql replacements]}]
    (reduce (fn [acc [k v]] (s/replace acc k v)) sql replacements)))

(def sql-replace-from-file
  (fn [file replacements]
    (sql-replace (conj replacements [:sql (slurp file)]))))

(sql-replace-from-file
 "/tmp/example.sql"
 {:replacements {"schema_name" "production"
                 "table_name"  "employees"
                 "field_name"  "name"
                 "field_value" "nelo"}})