求援：asp.net core3.1查询Oracle数据库始终出错

Question

问题遇到的现象和发生背景

我在使用asp.net core3.1查询Oracle数据库始终出错，找不到原因。

查询语句单独复制在Oracle运行正确。查询语句如下：
string sql = "select NAME,nvl2(VALUE,VALUE,'fyp') VALUE,nvl2(ATTRIBUTE6,ATTRIBUTE6,'fyp') ATTRIBUTE6 from propertymodel where NAME in ('"+ _parameter+"','" + _parameter + "-1','" + _parameter + "-2') and PARTREF='"+ _item+"';";

问题相关代码，请勿粘贴截图

using Microsoft.Extensions.Configuration;
using Oracle.ManagedDataAccess.Client;
using System;
using System.Collections.Generic;
using System.Data;
using System.IO;
/// <summary>
        /// 执行查询操作，返回SqlDataReader
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="parameters"></param>
        /// <returns></returns>
        public static OracleDataReader ExecuteReader(string sql, IDataParameter[] parameters)//params OracleParameter[] parameters)
            {
                OracleConnection connection = new OracleConnection(dbConnectionString);
                connection.Open();
                OracleCommand command = new OracleCommand(sql, connection);
                if (parameters != null && parameters.Length > 0)
                {
                    command.Parameters.AddRange(parameters);
                }
                try
            {
                //这句始终出错
                OracleDataReader reader = command.ExecuteReader(CommandBehavior.CloseConnection);
                    command.Parameters.Clear();
                    return reader;
                }
                catch(Exception ex)
                {
                    command.Parameters.Clear();
                    connection.Close();
                    return null;
                }
            }

运行结果及报错内容

报的错误是：Message = "ORA-00911: 无效字符"

我的解答思路和尝试过的方法

我想要达到的结果

Answer 1

value视乎是oracle关键字？用中括号扩起试试

string sql = "select NAME,nvl2([VALUE],[VALUE],'fyp') [VALUE],nvl2(ATTRIBUTE6,ATTRIBUTE6,'fyp') ATTRIBUTE6 
from propertymodel 
where NAME in ('"+ _parameter+"','" + _parameter + "-1','" + _parameter + "-2') and PARTREF='"+ _item+"';";