Java SQL未命名参数语法

我查了两次为什么会这样？我有正确数量的未命名参数，列名称正确

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您的SQL语法有错误；检查手册 对应于您的MariaDB服务器版本，具有正确的语法to 在“？，？，？，？，？，？，？）”附近使用在第1行

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At

returno=判决执行更新（sql）

尝试删除参数

sql

您可能编辑了问题，尝试了一些方法。一个干净的版本是：

public void adiciona(Libro libro) {
    
    // Not needed:
    String sqlQuery = "select count(*) from libro where isbn = ?";
    try (PreparedStatement sentencia = connection.createStatement(sqlQuery)) {
        sentencia.setInt(libro.getIsbn());
        try (ResultSet resultSet = sentencia.executeQuery()) {
            if (resultSet.next() && sentencia.getLong(1) > 0L) {
                return;
            }
        }
    } catch (SQLException e) {
        throw new RuntimeException(e);
    }

   String sql = "insert into libro (isbn, titulo, precio, stock, cod_categoria, cod_editorial) "
        + "values (?, ?, ?, ?, ?, ?)";
    try (PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
        preparedStatement.setInt(1, libro.getIsbn());
        preparedStatement.setString(2, libro.getTitulo());
        preparedStatement.setDouble(3, libro.getPrecio());
        preparedStatement.setInt(4, libro.getStock());
        preparedStatement.setInt(5, libro.getCod_categoria());
        preparedStatement.setInt(6, libro.getCod_editorial());
        
        int retorno = preparedStatement.executeUpdate();
        if (retorno > 0) {
            System.out.println("added")
        } else {
            System.out.println("not added.");
        }
    } catch (SQLIntegrityConstraintViolationException e) {
        System.out.printf("error duplicado: %s\n", e);
        throw new RuntimeException(e);
    } catch (SQLException e2) {
        throw new RuntimeException(e2);
    }
}

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@EmanuelMosby Note

和&sentencia.getLong（1）>0L

我后来添加到了不需要的代码中。

public void adiciona(Libro libro) {
    
    // Not needed:
    String sqlQuery = "select count(*) from libro where isbn = ?";
    try (PreparedStatement sentencia = connection.createStatement(sqlQuery)) {
        sentencia.setInt(libro.getIsbn());
        try (ResultSet resultSet = sentencia.executeQuery()) {
            if (resultSet.next() && sentencia.getLong(1) > 0L) {
                return;
            }
        }
    } catch (SQLException e) {
        throw new RuntimeException(e);
    }

   String sql = "insert into libro (isbn, titulo, precio, stock, cod_categoria, cod_editorial) "
        + "values (?, ?, ?, ?, ?, ?)";
    try (PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
        preparedStatement.setInt(1, libro.getIsbn());
        preparedStatement.setString(2, libro.getTitulo());
        preparedStatement.setDouble(3, libro.getPrecio());
        preparedStatement.setInt(4, libro.getStock());
        preparedStatement.setInt(5, libro.getCod_categoria());
        preparedStatement.setInt(6, libro.getCod_editorial());
        
        int retorno = preparedStatement.executeUpdate();
        if (retorno > 0) {
            System.out.println("added")
        } else {
            System.out.println("not added.");
        }
    } catch (SQLIntegrityConstraintViolationException e) {
        System.out.printf("error duplicado: %s\n", e);
        throw new RuntimeException(e);
    } catch (SQLException e2) {
        throw new RuntimeException(e2);
    }
}