Question

I’m having trouble doing anything with clojure.contrib.sql beyond establishing a connection.

I have a mysqld running on localhost:3306 with a database called clj_db.
The user ‘clj_user’@’localhost’ with password ‘clj_pass’ can access this database.

When trying to “select * from clj_table” I get a “com.mysql.jdbc.exceptions.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘????????????????’ at line 1”.

What am I doing wrong?

clj_db.clj_table

CREATE TABLE `clj_table` (
  `col_one` int(11) NOT NULL,
  `col_two` int(11) NOT NULL
) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

mysql_test.clj

(ns test.mysql
    (:use clojure.contrib.sql)
)

(def db-settings
    {:classname "com.mysql.jdbc.Driver"
    :subprotocol "mysql"
    :subname "//localhost:3306/clj_db"
    :user "clj_user"
    :password "clj_pass"})

(with-connection db-settings
    (with-query-results rs ["select * from clj_table"]
        (dorun (map #(println (:col_one :col_two %)) rs))
    ))

Output

Exception in thread "main" com.mysql.jdbc.exceptions.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '????????????????' at line 1 (mysql_test.clj:0)
   at clojure.lang.Compiler.eval(Compiler.java:4658)
   at clojure.lang.Compiler.load(Compiler.java:4972)
   at clojure.lang.Compiler.loadFile(Compiler.java:4939)
   at clojure.main$load_script__7405.invoke(main.clj:213)
   at clojure.main$script_opt__7442.invoke(main.clj:265)
   at clojure.main$main__7466.doInvoke(main.clj:346)
   at clojure.lang.RestFn.invoke(RestFn.java:441)
   at clojure.lang.Var.invoke(Var.java:367)
   at clojure.lang.AFn.applyToHelper(AFn.java:179)
   at clojure.lang.Var.applyTo(Var.java:476)
   at clojure.main.main(main.java:37)
Caused by: com.mysql.jdbc.exceptions.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '????????????????' at line 1
   at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1048)
   at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3563)
   at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3495)
   at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1959)
   at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2113)
   at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2687)
   at com.mysql.jdbc.ConnectionImpl.configureClientCharacterSet(ConnectionImpl.java:1859)
   at com.mysql.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:3593)
   at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2199)
   at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:784)
   at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:350)
   at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:284)
   at java.sql.DriverManager.getConnection(libgcj.so.10)
   at clojure.contrib.sql.internal$get_connection__218.invoke(internal.clj:85)
   at clojure.contrib.sql.internal$with_connection_STAR___226.invoke(internal.clj:102)
   at test.mysql$eval__386.invoke(mysql_test.clj:12)
   at clojure.lang.Compiler.eval(Compiler.java:4642)
   ...10 more

Answer 1

I’ve switched to Sun’s JDK6 instead of GIJ.

I got “com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure”.
I found this thread, which really helped me a lot.

I’ve added the option “-Djava.net.preferIPv4Stack=true” and it now works fine.

Thanks everybody!