Question

我尝试为MS SQL创建存储过程

CREATE PROCEDURE YEARENDPROCESSING
AS
DECLARE @VAR AS VARCHAR(9)    

DECLARE ACURSOR CURSOR FOR 
SELECT COLUMN FROM TABLEA

OPEN ACURSOR 
 FETCH NEXT FROM ACURSOR INTO  @VAR
while @@FETCH_STATUS = 0
    BEGIN
    INSERT INTO TABLEB SELECT * FROM TABLEC WHERE TABLEC.COLUMNC = @VAR
FETCH NEXT FROM ACURSOR INTO @VAR
    END
    CLOSE ACURSOR 
    DEALLOCATE ACURSOR

假设TableC列和TableB具有相同的列我得到结果说X行受到影响但在实际的表格中，我什么也看不见。

我有一个新的发现

CREATE PROCEDURE YEARENDPROCESSING
AS
DECLARE @VAR AS VARCHAR(9)    

DECLARE ACURSOR CURSOR FOR 
SELECT COLUMN FROM TABLEA

OPEN ACURSOR 
 FETCH NEXT FROM ACURSOR INTO  @VAR
while @@FETCH_STATUS = 0
    BEGIN
    INSERT INTO TABLEB SELECT * FROM TABLEC WHERE TABLEC.COLUMNC = @VAR
    DELETE TABLEF where columnf = @VAR
FETCH NEXT FROM ACURSOR INTO @VAR
    END
    CLOSE ACURSOR 
    DEALLOCATE ACURSOR

对于插入而言，x行会受到影响，而对于删除

，x行会受到影响

但实际的事实是在物理表本身中无法看到插入结果。我可以看到删除删除查询的结果。谁知道为什么？

Answer 1

您的代码不应该有光标。你可以这样做：

CREATE PROCEDURE dbo.YearEndProcessing
AS
BEGIN
  SET NOCOUNT ON;

  INSERT dbo.TableB(column1, column2, ...)
    SELECT column1, column2, ...
    FROM dbo.TableA;
END
GO

嗯，你改变了代码，现在有第三个表，所以让我在没有光标的情况下再试一次：

CREATE PROCEDURE dbo.YearEndProcessing
AS
BEGIN
  SET NOCOUNT ON;

  INSERT dbo.TableB(column1, column2, ...)
    SELECT c.column1, c.column2, ...
    FROM dbo.TableA AS a
    INNER JOIN dbo.TableC AS c
    ON a.[Column] = c.[ColumnC];
END
GO

或者：

CREATE PROCEDURE dbo.YearEndProcessing
AS
BEGIN
  SET NOCOUNT ON;

  INSERT dbo.TableB(column1, column2, ...)
    SELECT c.column1, c.column2, ...
    FROM dbo.TableC AS c
    WHERE EXISTS
    (
      SELECT 1 FROM dbo.TableA AS a
      WHERE a.[Column] = c.[ColumnC]
    );
END
GO

你不应该使用INSERT TABLE SELECT * FROM TABLE模式 - 将来很容易破坏（see this post for more details）。另请参阅this post about using a schema prefix以及有关游标用法的这些帖子 - 它应该保留用于实际需要它的情况，当您确实需要它时，请不要使用默认选项：

https://sqlblog.org/2012/01/26/bad-habits-to-kick-thinking-a-while-loop-isnt-a-cursor

http://www.sqlperformance.com/2012/07/t-sql-queries/running-totals

http://www.sqlperformance.com/2012/09/t-sql-queries/cursor-options

至于为什么你看到插入行但后来看不到数据，我怀疑你正在查看错误数据库中的表，错误的模式，或者你有多个数据库副本（发生了这种情况）在连接字符串中使用User Instance和AttachDbFileName选项时。）

MS SQL Store过程插入不起作用

1 个答案: