Getting error when using prepareStatement with interval in query

问题

When running this query SELECT SYSDATE + INTERVAL '7' DAY FROM DUAL; in a prepareStatement like this

    PreparedStatement ps =  connection.prepareStatement("select sysdate + interval ? day from dual" );      
    ps.setString(1, "7");
    ps.executeQuery();

It will throw an exception, that the syntax is not good, it clearly is, cuz i'm able to run the same query in sql-developer.

Is this a bug in PreparedStatement ? can i use prepared statements together with interval?

回答1:

The entire expression INTERVAL '7' DAY is a literal, you cannot simply replace a part of it with a variable (parameter). Use the function NUMTODSINTERVAL(?,'DAY') instead.

回答2:

PreparedStatement doesn't work with interval literals, so neither setInt nor setString works! http://docs.oracle.com/cd/B19306_01/server.102/b14200/sql_elements003.htm

For that reason if you want to dynamically change the days in your query (with interval literals), the only way is to concatenate that value.

In your example:

int yourDays = 7;
String query ="select sysdate + interval '" + yourDays + "' day from dual ";

Then you can use PreparedStatement if you need to add other parameters and to execute the query.

回答3:

It will work if you pass an int parameter multiplied by a fixed interval E.g.

select * from foo where (time + ? * INTERVAL '1' DAY) > current_timestamp

You can put days, hours whatever... and than setInt parameter

来源：https://stackoverflow.com/questions/29066015/getting-error-when-using-preparestatement-with-interval-in-query

标签

java

Oracle

prepared-statement

intervals