Question

我想编写一个Clojure查询，以便where子句中的lnam和fnam参数是双引号。我需要它们双引号，因为嵌入的名称包含单引号字符，如＆＃34; O＆＃39; BRIEN＆＃34;。

我一直在查看Clojure查询和在字符串中嵌入双引号的示例，但我找不到我想要的示例。

这在lein repl

中工作正常

gic-cmp.core=> (def lnam "O'BRIEN")
#'gic-cmp.core/lnam
gic-cmp.core=> (str """"lnam"""")
"O'BRIEN"

但是这不会在下面的查询中产生带引号的字符串。

(defn match-this-rec-with-last
    ""
    [gic-id lnam fnam search-date]
    (let [query (str (str "select g.* from gic_employees g where g.processed_date = '" search-date "' ")
                          (str "and g.gic_id = '" gic-id "' and g.last_name = ")
                          """"lnam""""
                          (str " and g.first_name = ")
                          (str """"fnam"""")
                          (str " order by g.processed_date desc "))]
      (println query)
      (j/query db
            [query])))

Answer 1

使用？对于查询参数，jdbc将正确地转义它们：

(defn match-this-rec-with-last
  ""
  [gic-id lnam fnam search-date]
  (let [query [(clojure.string/join " " ["select g.* from gic_employees g where g.processed_date = ?"
                                          "AND g.gic_id = ? and g.last_name = ?"
                                          "AND g.first_name = ?"
                                          "ORDER BY g.processed_date desc"])
               ;; values
               search-date gic-id lnam fnam]]
    (println query)
    (j/query db
             query)))

Answer 2

REPL显示str函数的返回值，并带有引号。

(str """"lnam"""")

这将返回2个空字符串，lnam和另外2个空字符串，并且都带有引号。

底层字符串是java.lang.String，在字符串中包含双引号的标准java方法是用反斜杠转义它。

user=> (str "test with \"quoted\" value")
"test with \"quoted\" value"
user=> (println (str "test with \"quoted\" value"))
test with "quoted" value

如何用嵌入的双引号组合Clojure查询

2 个答案: