SQL injection
Using a SQL update statement like this one (spacing is optional):

UPDATE players
   SET name = 'Smith, Steve', score = 42, active = TRUE
   WHERE jerseyNum = 99
Non-parameterized SQL is the GoTo statement of database programming. Don't do it, and make sure your coworkers don't either.
(require '[clojure.java.jdbc :as sql])
; Using h2database for this simple example.
(def db {:classname "org.h2.Driver"
         :subprotocol "h2:file"
         :subname "db/my-dbname"})
 
(sql/update! db :players {:name "Smith, Steve" :score 42 :active true} ["jerseyNum = ?" 99])
 
; As an alternative to update!, use execute!
(sql/execute! db ["UPDATE players SET name = ?, score = ?, active = ? WHERE jerseyNum = ?" "Smith, Steve" 42 true 99])