Invalid column index using PreparedStatement

问题

I am trying to query same data. But the preparedStatement thrown an SQLException about wrong indexing even though the index start from 1 as the documentation said.

Here is the function:

public List<Paper1> search(String keyword) throws NotConnectedException {

    List<Paper1> papers = new ArrayList<>();

    try {
        PreparedStatement searchKeyword = 
        connection.prepareStatement("SELECT title, registered FROM paper "
        + "WHERE title LIKE '%?%'");
        searchKeyword.setString(1, keyword);
        ResultSet rs = searchKeyword.executeQuery();

        while (rs.next()) {
            Paper1 p = new Paper1();
            p.setTitle(rs.getString("title"));
            p.setRegistered(rs.getDate("registered").toLocalDate());
            papers.add(p);
        }
        return papers;
    } catch (SQLException e) {
        e.printStackTrace();
        return null;
    }
}

The SQLException said, the wrong line is the

searchKeyword.setString(1, keyword);

because of the wrong column index

回答1:

Your question-mark place holder is inside single quotes, so it's being seen as a literal character - and not a place holder at all. When the statement is parsed the '%?%' is just a string and no bind variable is seen, so no bind variable can be set - there are no variables, so no variable with index 1.

You can use concatenation to fix this:

    PreparedStatement searchKeyword = 
    connection.prepareStatement("SELECT title, registered FROM paper "
    + "WHERE title LIKE '%' || ? || '%'");

回答2:

Print out the query string before executing it:

SELECT title, registered FROM paperWHERE title LIKE '%?%'

The answer should be obvious.

You need spaces to delimit keywords.

来源：https://stackoverflow.com/questions/43051975/invalid-column-index-using-preparedstatement