我该如何解决C＃中的SQLite查询问题？

Question

我尝试创建一个datagridview查询。但我有一些语法错误SQLite和 我不知道如何解决我的查询。

 string command3 = ""; 
     for (int y = year1; y <= year2; y++) 
     { 
      if (y > year1) 
      { 
       command3 += " UNION "; 
      } 
      command3 += "SELECT 'Въведени' AS 'Въведени/Изчислени', Station AS '№ на станция', strftime('%Y',Dat) AS 'Година', 'НМ' AS 'НМ/СР/НГ', (SELECT vkolmin FROM hydmes WHERE Station= '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat)=01) AS 'Януари', (SELECT vkolmin FROM hydmes WHERE Station= '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat)=02) AS 'Февруари', (SELECT vkolmin FROM hydmes WHERE Station= '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat)=03) AS 'Март', (SELECT vkolmin FROM hydmes WHERE Station= '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " strftime('%m',Dat)=04) AS 'Април', (SELECT vkolmin FROM hydmes WHERE Station= '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat)=05) AS 'Май', (SELECT vkolmin FROM hydmes WHERE Station= '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat)=06) AS 'Юни', (SELECT vkolmin FROM hydmes WHERE Station= '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat)=07) AS 'Юли', (SELECT vkolmin FROM hydmes WHERE Station= '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat)=08) AS 'Август', (SELECT vkolmin FROM hydmes WHERE Station= '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat)=09) AS 'Септември', (SELECT vkolmin FROM hydmes WHERE Station= '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat)=10) AS 'Октомври', (SELECT vkolmin FROM hydmes WHERE Station= '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat)=11) AS 'Ноември', (SELECT vkolmin FROM hydmes WHERE Station= '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat)=12) AS 'Декември'" 
      + "FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y 
      + " UNION" 
      + " SELECT 'Изчислени', Station, strftime('%Y',Dat), 'НМ', (SELECT min(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 01 LIMIT 1), (SELECT min(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 02 LIMIT 1), (SELECT min(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 03 LIMIT 1), (SELECT min(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 04 LIMIT 1), (SELECT min(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 05 LIMIT 1), (SELECT min(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 06 LIMIT 1), (SELECT min(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 07 LIMIT 1), (SELECT min(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 08 LIMIT 1), (SELECT min(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 09 LIMIT 1), (SELECT min(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 10 LIMIT 1), (SELECT min(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 11 LIMIT 1), (SELECT min(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 12 LIMIT 1)" 
      + "FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y 
      + " UNION" 
      + " SELECT 'Въведени', Station, strftime('%Y',Dat), 'СР', (SELECT vkolsre FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 01), (SELECT vkolsre FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 02), (SELECT vkolsre FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 03), (SELECT vkolsre FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 04), (SELECT vkolsre FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 05), (SELECT vkolsre FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 06), (SELECT vkolsre FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 07), (SELECT vkolsre FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 08), (SELECT vkolsre FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 09), (SELECT vkolsre FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 10), (SELECT vkolsre FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 11), (SELECT vkolsre FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 12)" 
      + "FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y 
      + " UNION" 
      + " SELECT 'Изчислени', Station, strftime('%Y',Dat), 'СР', (SELECT avg(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 01 LIMIT 1), (SELECT avg(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 02 LIMIT 1), (SELECT avg(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 03 LIMIT 1), (SELECT avg(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 04 LIMIT 1), (SELECT avg(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 05 LIMIT 1), (SELECT avg(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 06 LIMIT 1), (SELECT avg(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 07 LIMIT 1), (SELECT avg(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 08 LIMIT 1), (SELECT avg(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 09 LIMIT 1), (SELECT avg(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 10 LIMIT 1), (SELECT avg(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 11 LIMIT 1), (SELECT avg(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 12 LIMIT 1)" 
      + "FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y 
      + " UNION" 
      + " SELECT 'Въведени', Station, strftime('%Y',Dat), 'НГ', (SELECT vkolmax FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 01), (SELECT vkolmax FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 02), (SELECT vkolmax FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 3), (SELECT vkolmax FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 04), (SELECT vkolmax FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 05), (SELECT vkolmax FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 06), (SELECT vkolmax FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 07), (SELECT vkolmax FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 08), (SELECT vkolmax FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 09), (SELECT vkolmax FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 10), (SELECT vkolmax FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 11), (SELECT vkolmax FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 12)" 
      + "FROM hydmes WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y 
      + " UNION" 
      + " SELECT 'Изчислени', Station, strftime('%Y',Dat), 'НГ', (SELECT max(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 01 LIMIT 1), (SELECT max(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 02 LIMIT 1), (SELECT max(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 03 LIMIT 1), (SELECT max(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 04 LIMIT 1), (SELECT max(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 05 LIMIT 1), (SELECT max(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 06 LIMIT 1), (SELECT max(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 07 LIMIT 1), (SELECT max(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 08 LIMIT 1), (SELECT max(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 09 LIMIT 1), (SELECT max(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 10 LIMIT 1), (SELECT max(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 11 LIMIT 1), (SELECT max(vkol) FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y + " and strftime('%m',Dat) = 12 LIMIT 1)" 
      + "FROM hyddnev WHERE Station = '" + comboBox1.SelectedItem.ToString() + "' and strftime('%Y',Dat) = " + y; 
     } 
     command3 += " group by strftime('%Y',Dat)"; 

     SQLiteDataAdapter insertDat3 = new SQLiteDataAdapter(command3, Connection); 
      using (DataTable dt3 = new DataTable()) 
      { 
       insertDat3.Fill(dt3); 
       dataGridView1.DataSource = dt3.DefaultView; 
      } 

     } 

错误是：

System.Data.SQLite.SQLiteException（0X80004005）：SQL逻辑错误或丢失的数据库近 “的strftime”：语法错误

我有同样的使用MySql数据库的应用程序，只需从其他应用程序复制此查询，但SQLite语法与MySQL不同？

我不知道我在哪里以及如何修复查询。

Answer 1

对不起，我还不能评论，所以我会张贴这个答案。

首先，我同意上面的意见。只用您提供的示例代码很难帮助您解决问题。其次，不要将字符串直接连接到查询，因为存在SQL注入的风险。

说到这里，我已经有了一些像这样的情况，我的方法是直接在查询窗口中调试/测试我的查询。我建议你分开你的查询，由这些联盟“加入”，向他们提供实际的价值并逐一运行。如果一切正常，则完全运行查询。如果一切正常，那么问题必须在你的串联中。我总是喜欢以“分而治之”的方式处理我的问题，我喜欢分离并消除可能的原因。