com.mysql.jdbc.exceptions.MySQLSyntaxErrorException when using PreparedStatement

I am trying to execute a query that returns a student whose name and last name concatenated equal the search key parameter.

For that I am doing this in my class that manages anything related to the database for my Student class.

When the query is executed I am getting the error that follows:

com.mysql.jdbc.exceptions.MySQLSyntaxErrorException:

What's wrong? I have checked that's the correct way to use concat.

name and lastName are VARCHAR in the mysql database.

public static Student findStudent(String key) {
    if (key == null) return null;

    PreparedStatement preparedStatement = null;
    ResultSet rs = null;

    String selectSQL = "select * from project.students where concat(name, lastName) = ? ;";

    try {
      dbConnection = getDBConnection();

      preparedStatement = dbConnection.prepareStatement(selectSQL);
      preparedStatement.setString(1, key);

      Student student = null;
      rs = preparedStatement.executeQuery(selectSQL);
      if (rs.next()) {
          StudentDB.setStudentAttributes(student, rs);
      }

      return student;
    } catch(SQLException e) {
      e.printStackTrace();
    } finally {
      close();
      try {
          if (preparedStatement != null) preparedStatement.close();
          if (rs != null) rs.close();
      } catch(SQLException e) {
          e.printStackTrace();
      }
    }
    return null;
}