从查询而不是视图中选择列名

Question

是否可以从查询中获取列名，就像从视图中获取列名一样？视图示例如下..我不能使用视图示例，因为这些是由用户创建的查询，可能会经常修改。

SELECT * FROM sys.columns WHERE object_id = OBJECT_ID('dbo.ViewName')

提前谢谢你..

德里克。

Answer 1

如果您使用的是SQL Server2012或更高版本，则可以使用sp_describe_first_result_set。

此存储过程的基本要点涉及将正在运行的查询作为参数进行传递。然后，SQL Server描述它将返回的结果，包括列名、数据类型、大小等。

EXEC sp_describe_first_result_set N'SELECT * from my_table';

Answer 2

如果您使用的是SQL2012或更高版本，则可以使用sp_describe_first_result_set。例如：

sp_describe_first_result_set @tsql = N'EXEC dbo.usp_index'

将dbo.usp_index定义为：

CREATE PROCEDURE dbo.usp_index
AS 
    SELECT  object_id ,
          name ,
          type_desc
    FROM      sys.indexes

如果您使用的是2012年之前的版本，您可以使用CLR过程来实现类似的功能：

[Microsoft.SqlServer.Server.SqlProcedure]
public static void usp_describe_first_result_set(string sqlCommandText)
{
    using (SqlConnection connection = new SqlConnection("context connection=true"))
    {
        connection.Open();
        SqlCommand cmd = new SqlCommand();
        DataTable schemaTable;
        SqlDataReader myReader;

        //Retrieve records from the Employees table into a DataReader.
        cmd.Connection = connection;
        cmd.CommandText = sqlCommandText;
        myReader = cmd.ExecuteReader(CommandBehavior.SingleResult);


        //Retrieve column schema into a DataTable.
        schemaTable = myReader.GetSchemaTable();
        int rowCount = 0;

        //For each field in the table...
        foreach (DataRow myField in schemaTable.Rows)
        {
            int column = 0;

            SqlDataRecord dataRow = new SqlDataRecord(
              new SqlMetaData("name", SqlDbType.VarChar, 256),
              new SqlMetaData("column_ordinal", SqlDbType.VarChar, 256),
              new SqlMetaData("max_length ", SqlDbType.VarChar, 256),
              new SqlMetaData("precision", SqlDbType.VarChar, 256),
              new SqlMetaData("scale", SqlDbType.VarChar, 256),
              new SqlMetaData("is_unique", SqlDbType.VarChar, 256),
              new SqlMetaData("is_key ", SqlDbType.VarChar, 256),
              new SqlMetaData("source_server", SqlDbType.VarChar, 256),
              new SqlMetaData("source_database", SqlDbType.VarChar, 256),
              new SqlMetaData("source_column", SqlDbType.VarChar, 256),
              new SqlMetaData("source_schema ", SqlDbType.VarChar, 256),
              new SqlMetaData("source_table", SqlDbType.VarChar, 256),
              new SqlMetaData("is_nullable ", SqlDbType.VarChar, 256),
              new SqlMetaData("is_aliased ", SqlDbType.VarChar, 256),
              new SqlMetaData("is_computed_column ", SqlDbType.VarChar, 256),
              new SqlMetaData("is_identity_column", SqlDbType.VarChar, 256),
              new SqlMetaData("is_autoincrement ", SqlDbType.VarChar, 256),
              new SqlMetaData("is_rowversion ", SqlDbType.VarChar, 256),
              new SqlMetaData("is_hidden ", SqlDbType.VarChar, 256),
              new SqlMetaData("is_long ", SqlDbType.VarChar, 256),
              new SqlMetaData("is_readonly ", SqlDbType.VarChar, 256),
              new SqlMetaData("system_type_name", SqlDbType.VarChar, 256),
              new SqlMetaData("xml_collection_database", SqlDbType.VarChar, 256),
              new SqlMetaData("xml_collection_schema", SqlDbType.VarChar, 256),
              new SqlMetaData("xml_collection_name", SqlDbType.VarChar, 256),
              new SqlMetaData("is_column_set ", SqlDbType.VarChar, 256));


            //For each property of the field...
            foreach (DataColumn myProperty in schemaTable.Columns)
            {
                //Display the field name and value.
                if (!myProperty.ColumnName.Contains("Provider") && !myProperty.ColumnName.Contains("Assembly") && !myProperty.ColumnName.Equals("DataType"))
                {
                    dataRow.SetValue(column, myField[myProperty].ToString());

                    column++;
                }
            }

            if (rowCount == 0)
            {
                SqlContext.Pipe.SendResultsStart(dataRow);
            }

            SqlContext.Pipe.SendResultsRow(dataRow);

            rowCount++;
        }


        SqlContext.Pipe.SendResultsEnd();
    }
}