MySQL Java PreparedStatement插入（如果不存在）

Question

i try to fill data into my databse. But i don't want dublicates based on the time. I don't care about the dublicates, because i don't lose any data. After a long search i finally found, that you can't use WHERE NOT EXIST with an INSERT INTO .

But now i got the next problem. I tried these two approaches but none of these works.

      /*
      preparedStatement = connect.prepareStatement("IF NOT EXISTS(SELECT * FROM gpsdata.data where time=?) "
            + "Begin "
            + "INSERT INTO gpsdata.data VALUES (default, ?, ? , ?, ?, ?, ?, ?, ?) "+
              "END");
      */
      preparedStatement = connect.prepareStatement("INSERT INTO gpsdata.data VALUES (default, ?, ? , ?, ?, ?, ?, ?, ?) "
            + "SELECT ? FROM gpsdata.data WHERE NOT EXISTS(SELECT * FROM gpsdata.data where time = ?)");

Both gave me some mysql syntax errors. I can't figure out what is wrong. I am new to mysql. The last try gave me at least a different error:

MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual... ... to use near 'SELECT 1448982118099 WHERE NOT EXISTS(SELECT * FROM gpsdata.data where time =14') at line 1

Before the check for dublicates, the code was running fine. So it should be the new statement.

Regards, Eric

EDIT: I don't want to copy my data into an other table.

Answer 1

? is not a valid parameter in SELECT ? . You have to literally name a column.

Answer 2

In order to connect insert with parameters part with condition part you can use select from dual . I have tried the statement below with Oracle.

preparedStatement = connect.prepareStatement("INSERT INTO gpsdata.data select 'default', ?, ? , ?, ?, ?, ?, ?, ? from dual
            WHERE NOT EXISTS(SELECT * FROM gpsdata.data where time = ?)");

ps: please be aware that you use time variable twice.