Question

我搜索了这个问题，但我想任何人都面临过这个问题。我正在尝试使用ExecuteQuery进行IN操作。

IEnumerable<TAssets> results = db.ExecuteQuery<TAssets>
("SELECT * FROM TAssets " +
 " WHERE AssetId not in (select MatchedAssetId from TMatches where LabelId = {0})" +
 "       and CompanyId in ({1}) ",
labelid,
string.Join(",", companyIdList)
);
return results.ToList();

问题是 string.Join（“，”，companyIdList）返回'61,70'。然后它尝试将其转换为整数。为什么？我该怎么办？

ERROR:Conversion failed when converting the nvarchar value '61,70' to data type int.
System.Data.SqlClient.SqlException (0x80131904): Conversion failed when converting the nvarchar value '61,70' to data type int.
  at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
  at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose)
  at System.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady)
  at System.Data.SqlClient.SqlDataReader.TryHasMoreRows(Boolean& moreRows)
  at System.Data.SqlClient.SqlDataReader.TryReadInternal(Boolean setTimeout, Boolean& more)
  at System.Data.SqlClient.SqlDataReader.Read()
  at System.Data.Linq.SqlClient.ObjectReaderCompiler.ObjectReaderBase`1.Read()
  at System.Data.Linq.SqlClient.ObjectReaderCompiler.ObjectReader`2.MoveNext()
  at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
  at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)

任何建议？或者你能告诉我使用ExecuteQuery的IN运算符吗？

Answer 1

这里的事情是它们是参数化的，这通常是一件好事。

我不是说这是最好的解决方案，但你应该可以这样做：

// Note that the first {} is escaped.
var sql = string.Format(
                    "SELECT * FROM TAssets WHERE AssetId not in (select MatchedAssetId from TMatches where LabelId = {{0}}) and CompanyId in ({0})",
                    string.Join(",", companyIdList));
IEnumerable<TAssets> results = db.ExecuteQuery<TAssets>(sql, labelid);
return results.ToList();

它实际上做的是它将companyIds添加到sql字符串而不是让ExecuteQuery参数化它。只要注意sql注入，并确保你的int数组中只有companyId。

sql - 变量将是：

SELECT * FROM TAssets WHERE AssetId not in (select MatchedAssetId from TMatches where LabelId = {0}) and CompanyId in (61,70)

Answer 2

您正在构建的声明导致：

"SELECT * FROM TAssets WHERE AssetId not in (select MatchedAssetId from TMatches where LabelId = 1) and CompanyId in ('61,70')"

您需要分别解释每个值，以便输出如下：

"SELECT * FROM TAssets WHERE AssetId not in (select MatchedAssetId from TMatches where LabelId = 1) and CompanyId in ('61','70')"

这一行

string.Join("','", companyIdList)

结合领先和结束＆＃39;应该做的。

更好的方法是动态创建SqlParameters但

C＃ExecuteQuery：如何使用IN运算符？

2 个答案: