Question

我无法手动将CurrentSystemTime添加到我的查询中。 Query存储在字符串变量中。但是，分段部分给出了错误：

查询为：

<?xml version="1.0"?>
<QUANDATASET>
  <XMLFILE>
  <DATASET>
  <GROUPDATA>
    <GROUP>
      <METHODDATA/>
      <SAMPLELISTDATA>
        <SAMPLE id="1" groupid="1" name="Routine_2016_05_30_002">
          <COMPOUND id="1" sampleid="1" groupid="1" name="Leu">
            <PEAK foundscan="0" analconc="0.023423456">
              <ISPEAK/>
            </PEAK>
          </COMPOUND>
          <COMPOUND id="2" sampleid="1" groupid="1" name="Iso">
             <PEAK foundscan="0" analconc="0.123456789">
               <ISPEAK/>
             </PEAK>
          </COMPOUND>
          <COMPOUND id="3" sampleid="1" groupid="1" name="Thre">
          ...
          ...
          ...
        <SAMPLE id="2" groupid="1" name="Routine_2016_05_30_003">
          <COMPOUND id="1" sampleid="2" groupid="1" name="Leu">
          ...
          ...
          ...

问题部分：

ASD.eventDateTime＆gt; =＆＃39;＆＃34; +   DateTime.Today.ToString（＆＃34; yyyy-MM-dd h：mm：ss＆＃34;）+＆＃34;＆＃39;

错误是：

将文本表示为unicode字符Newline in constant。

Answer 1

您忘记使用@启动字符串的第二部分，这就是编译器修改换行符无效的原因：

string myQuery= @"SELECT MAX(ASD.eventDateTime) AS second, R.resourceID,R.resourceLoginID,ASD.agentID
                  FROM AgentStateDetail AS ASD INNER JOIN 
                  Resource AS R ON ASD.agentID = R.ResourceID WHERE ASD.eventDateTime >='" + DateTime.Today.ToString("yyyy-MM-dd h:mm:ss") + @"'AND ASD.eventDateTime <='2016-10-18 23:59:59' 
                  GROUP BY R.ResourceID,R.resourceLoginID,ASD.agentID"

Answer 2

您可以使用参数化查询，如下所示

string sql = "SELECT MAX(ASD.eventDateTime) AS second, R.resourceID, R.resourceLoginID, ASD.agentID FROM AgentStateDetail AS ASD INNER JOIN Resource AS R ON ASD.agentID = R.ResourceID WHERE ASD.eventDateTime >= @dateTimeStart AND ASD.eventDateTime <= @dateTimeEnd GROUP BY R.ResourceID,R.resourceLoginID,ASD.agentID";

using (SqlConnection connection = new SqlConnection(/* connection info */))
using (SqlCommand command = new SqlCommand(sql, connection))
{
    var dateTimeStart = new SqlParameter("dateTimeStart", SqlDbType.DateTime);
    dateTimeStart.Value = new DateTime("yyyy-MM-dd h:mm:ss");

    var dateTimeEnd = new SqlParameter("dateTimeEnd", SqlDbType.DateTime);
    dateTimeEnd.Value = new DateTime("yyyy-MM-dd h:mm:ss");

    command.Parameters.Add(dateTimeStart);
    command.Parameters.Add(dateTimeEnd);
    var results = command.ExecuteReader();
}

具有DateTime字符串的查询的Concat字符串

2 个答案: