c# - Nested SELECT Issue

Question

I am having a small issue with SqlServerCe. When using the below sqlString to perform a ExecuteNonQuery(); command I get the error below.

string sqlString = "INSERT INTO Images (UID, Name) " +
            "VALUES ((SELECT ID FROM Contributors WHERE ID = @UID), @Name);";

gives this error:

There was an error parsing the query. [ Token line number = 1,Token line offset = 41,Token in error = SELECT ]

Any suggestions?

Method

public static void InsertImage(Contributor contObj, string ImageName)
{
    string sqlString = "INSERT INTO Images (UID, Name) " +
        "VALUES ((SELECT ID FROM [Contributors] WHERE ID = @UID), @Name);";
    using (SqlCeConnection sqlConnection =
        new SqlCeConnection(WebConfigurationManager.ConnectionStrings["DefaultSQL"].ConnectionString))
    {
        SqlCeCommand sqlCommand = new SqlCeCommand(sqlString, sqlConnection);
        sqlCommand.Parameters.AddWithValue("@UID", contObj.ID);
        sqlCommand.Parameters.AddWithValue("@Name", ImageName);
        sqlConnection.Open();
        sqlCommand.ExecuteNonQuery();
        sqlConnection.Close();
    }
}

Answer 1

为什么在这里使用嵌套选择？由于@UID已经引用了您选择的 ID 列，您不能这样做：

INSERT INTO Images (UID, Name) 
VALUES (@UID, @Name)

如果您真的必须使用选择，请查看 bluefeet 的答案。他提供了您指定的参数 ( @Name) 作为要插入的值之一，所以没问题。

Answer 2

你会想要使用INSERT INTO...SELECT..FROM

string sqlString = "INSERT INTO Images (UID, Name) " +
            "SELECT ID, @Name FROM Contributors WHERE ID = @UID;";

如果您已经知道 的值@ID，那么您可以使用INSERT INTO... VALUES...查询

INSERT INTO Images (UID, Name)
VALUES (@UID, @Name)

编辑，这是您的更新查询代码

public static void InsertImage(Contributor contObj, string ImageName)
{
    string sqlString = "INSERT INTO Images (UID, Name) " +
        "VALUES (@UID, @Name)";
    using (SqlCeConnection sqlConnection =
        new SqlCeConnection(WebConfigurationManager.ConnectionStrings["DefaultSQL"].ConnectionString))
    {
        SqlCeCommand sqlCommand = new SqlCeCommand(sqlString, sqlConnection);
        sqlCommand.Parameters.AddWithValue("@UID", contObj.ID);
        sqlCommand.Parameters.AddWithValue("@Name", ImageName);
        sqlConnection.Open();
        sqlCommand.ExecuteNonQuery();
        sqlConnection.Close();
    }
}

Answer 3

你可以这样做：

string sqlString = @"INSERT INTO Images(UID, Name)
                     SELECT ID, @Name
                     FROM Contributors
                     WHERE ID = @UID"