Question

我正在阅读某人的代码，但我不太明白。

for (var i = 0; i < tbl.Columns.Count; i++)
{
    //If you're at the first column 
    if (i == 0)
    {
        row[i] = colorTable[rowNum];
    }
    else
    {
        row[i] = currentRow[rowNum, i + 1].Text;
    }
}

如果将return设置为整数，下一行是什么意思？如何将@return设置为存储过程？是否调用存储过程？

Answer 1

是的，调用存储过程，返回值存储在2017-04-04 16:59:56.185045: W c:\tf_jenkins\home\workspace\nightly-win\device\cpu\os\windows\tensorflow\core\platform\cpu_feature_guard.cc:45] The TensorFlow library wasn't compiled to use SSE instructions, but these are available on your machine and could speed up CPU computations. 2017-04-04 16:59:56.185185: W c:\tf_jenkins\home\workspace\nightly-win\device\cpu\os\windows\tensorflow\core\platform\cpu_feature_guard.cc:45] The TensorFlow library wasn't compiled to use SSE2 instructions, but these are available on your machine and could speed up CPU computations. 2017-04-04 16:59:56.186551: W c:\tf_jenkins\home\workspace\nightly-win\device\cpu\os\windows\tensorflow\core\platform\cpu_feature_guard.cc:45] The TensorFlow library wasn't compiled to use SSE3 instructions, but these are available on your machine and could speed up CPU computations. 2017-04-04 16:59:56.187141: W c:\tf_jenkins\home\workspace\nightly-win\device\cpu\os\windows\tensorflow\core\platform\cpu_feature_guard.cc:45] The TensorFlow library wasn't compiled to use SSE4.1 instructions, but these are available on your machine and could speed up CPU computations. 2017-04-04 16:59:56.187629: W c:\tf_jenkins\home\workspace\nightly-win\device\cpu\os\windows\tensorflow\core\platform\cpu_feature_guard.cc:45] The TensorFlow library wasn't compiled to use SSE4.2 instructions, but these are available on your machine and could speed up CPU computations. 2017-04-04 16:59:56.188138: W c:\tf_jenkins\home\workspace\nightly-win\device\cpu\os\windows\tensorflow\core\platform\cpu_feature_guard.cc:45] The TensorFlow library wasn't compiled to use AVX instructions, but these are available on your machine and could speed up CPU computations.

中

正如documentation所说：

过程可以返回一个称为返回码的整数值，以指示过程的执行状态。您可以使用RETURN语句指定过程的返回码。与OUTPUT参数一样，必须在执行过程时将返回码保存在变量中，以便在调用程序中使用返回码值。例如，数据类型为int的赋值变量@result用于存储过程my_proc的返回码，例如：
@return
返回代码通常用于程序中的控制流程块，以便为每种可能的错误情况设置返回代码值。您可以在Transact-SQL语句之后使用@@ ERROR函数来检测在执行语句期间是否发生错误。

Answer 2

从存储过程返回return value。如果在过程中未显式返回值（例如return 2;），则它将返回0表示执行成功，如果遇到错误则返回负值。

参考：

return (Transact-SQL)

以下是一些简单的例子：

create proc dbo.AllGood as
begin;
  select 1 as One into #temp;
end;
go
create proc dbo.ReturnOneForOdd (@i int) as
begin;
  if (@i % 2) = 1 return 1;
end;
go
create proc dbo.DivByZero as
begin;
  begin try
    select 1/0;
  end try
  begin catch
  end catch;
end;
go

declare @r int;

exec @r = dbo.AllGood;
select @r as AllGood; /* returns 0 */

exec @r = dbo.ReturnOneForOdd 1 ;
select @r as ReturnOneForOdd; /* returns 1 */

exec @r = dbo.ReturnOneForOdd 2;
select @r as ReturnOneForOdd; /* returns 0 */

exec @r = dbo.DivByZero;
select @r as DivByZero; /* returns -6 */

rextester演示：http://rextester.com/WPNHX39195

Answer 3

检查this link以获取有关将存储过程输出存储到变量的更多详细信息。以OUTPUT变量作为参数的存储过程。

这个查询在SQL Server中做了什么？

3 个答案: