查询值和目标字段的数量不相同（联合）

Question

遇到此 SQL 错误 - 查询值和目标字段的数量不同（联合）。使用 Access 数据库。 programList 表中只有两个字段 - userID 和 programID。在我的cs文件中使用参数。这是完整的方法：

public void AddProgramList (string program, int userID)
{
    dbConnection.Open();

    string sqlStmt = "INSERT INTO programs (program) ";
    sqlStmt += "VALUES (@program)";
    string sqlStmt2 = "INSERT INTO programList (userID, programID) " +
                      "SELECT userID " +
                      "FROM users" +
                      "WHERE userID = @userID " +
                      "UNION " +
                      "SELECT programID " +
                      "FROM programs" +
                      "WHERE program = @program;";

    OleDbCommand dbCommand = new OleDbCommand(sqlStmt, dbConnection);

    OleDbParameter param = new OleDbParameter("@program", program);

    dbCommand.Parameters.Add(param);

    dbCommand.Parameters.Add(new OleDbParameter("@userID", userID));

    OleDbCommand dbCommand2 = new OleDbCommand(sqlStmt2, dbConnection);

    OleDbParameter param2 = new OleDbParameter("@program", program);

    dbCommand2.Parameters.Add(param2);

    dbCommand2.Parameters.Add(new OleDbParameter("@userID", userID));


    dbCommand.ExecuteNonQuery();

    dbCommand2.ExecuteNonQuery();

    dbConnection.Close();
}

Answer 1

如果你打印出 SQL，你会看到：

INSERT INTO programList (userID, programID) " +
SELECT userID FROM usersWHERE userID = @userID UNION SELECT programID FROM programsWHERE program = @program;

错误应该很明显。您可能没有名为usersWHERE 的表。

当我看到问题时，您正在尝试插入 两个 列。所以，我想你打算：

INSERT INTO programList (userID, programID)
    SELECT userID, programID
    FROM users, programs
    WHERE userID = @userID AND program = @program;

或者，更简单地说：

INSERT INTO programList (userID, programID)
    SELECT @userID, programid
    FROM programs
    WHERE program = @program;