Question

我在SQL中经常创建临时表，我正在研究一种为表定义自动生成列名和数据类型的方法，所以我不必每次都查看它们。

例如我跑：

SELECT CustomerID
  ClientID,
  FirstName
  LastName
INTO #Test
From dbo.Customer

最初使用我需要的相应列和数据设置临时表。一旦我完成了所有工作，我就会重新进入并取出INTO语句并写下以下内容：

CREATE TABLE #Test
(
...
...
);

我想找到一种从初始创建临时表中自动生成列名和数据类型的方法。现在，由于我最初插入自动创建的临时表，我使用它：

EXEC tempdb..sp_help '#Test';

这给了我所需的一切，而不必查看所有列数据类型，但我想知道是否有一种方法可以自动生成列名这样的东西。所以auto gen会产生：

CustomerID int,
ClientID int,
FirstName varchar(50),
LastName varchar(50)

这样我就可以将其复制并粘贴到我的create table语句中。

Answer 1

这可能会给你一个开始：

DECLARE @viewname VARCHAR(50);
SET @viewname ='tableorviewname';
SELECT  c.name + ' '+ t.name + 
case t.name  
WHEN 'varchar' THEN '('+CAST(c.max_length AS VARCHAR(3) )+'),'
ELSE ',' 
end
FROM sys.columns c
INNER JOIN sys.types AS t ON c.system_type_id = t.system_type_id
WHERE object_id = (SELECT object_id from sys.objects where name = @viewname)
ORDER BY c.column_id

编辑：TEMP TABLES：

临时表略有不同，例如这在sql 2008中适用于名为#tv_source的临时表

DECLARE @viewortablename VARCHAR(50);
SET @viewortablename ='tempdb..#tv_source';
SELECT  c.name + ' '+ t.name + 
case t.name  
WHEN 'varchar' THEN '('+CAST(c.max_length AS VARCHAR(3) )+'),'
ELSE ',' 
end
FROM tempdb.sys.columns c
INNER JOIN sys.types AS t ON c.system_type_id = t.system_type_id
WHERE object_id =  object_id(@viewortablename)
ORDER BY c.column_id

注意：这给出了一个以逗号分隔的列表，但没有尝试删除最后一个逗号，它只提供一个列表，您可能希望将其放在字符串上并进行操作等，然后用作动态sql或财产以后。不过，它应该让你开始你想做的事情。

对于其他人，请注意，sql 2000不能正确显示长度，例如在varchar（45）上，它只会列出varchar部分，我没有尝试为此问题重做。

Answer 2

SELECT
', ['+ac.name+'] '+Type_Name(User_type_id)+
CASE WHEN Type_Name(User_type_id) = 'Decimal' 
      THEN +'('+CONVERT(Varchar(4),ac.Precision)+','+CONVERT(Varchar(4),ac.Scale)+')' 
      WHEN Type_Name(User_type_id) IN 
            ('tinyint','smallint','int','real','money','float','numeric','smallmoney','DateTime') 
      THEN ''
      ELSE +'('+CONVERT(Varchar(4),ac.Max_Length)+')' 
END AS TableColumn
FROM Tempdb.sys.all_columns AS ac
      INNER JOIN Tempdb.Sys.SysObjects AS so
            ON so.ID = ac.Object_ID
WHERE 1 = 1
AND so.Name = '##YourTempTableGoesHere'

Answer 3

...我已经创建了一个函数，该函数可以输出列和数据类型的列表，如果对象是表，那对您有用吗？

CREATE FUNCTION [dbo].[fnDiscoverColumns]
( @PObjectName NVARCHAR(300) )

RETURNS @Data TABLE ( ColumnList NVARCHAR(350) )

AS
BEGIN

DECLARE @PObjectID TABLE  ( [object_id] INT )
INSERT @PObjectID ( [object_id] )

SELECT [object_id] FROM sys.objects AS O WHERE O.name = @PObjectName AND O.type = 'U'

DECLARE @PObjectDetails TABLE ( [RowNo] INT,[ColumnName] NVARCHAR(300),[XType] INT,[DataType] NVARCHAR(100),[system_type_id] INT,[user_type_id] INT,[MaxLength] NVARCHAR(5),[Precision] INT,[Scale] INT,[ColumnList] NVARCHAR(300) )

INSERT @PObjectDetails ( [RowNo],[ColumnName],[XType],[DataType],[system_type_id],[user_type_id],[MaxLength],[Precision],[Scale],[ColumnList] )

SELECT DISTINCT
ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) AS 'RowNo',
C.name AS 'ColumnName',
T.xtype AS 'XType',
UPPER(T.name) AS 'DataType',
C.system_type_id,
C.user_type_id,
CASE WHEN C.max_length < 0 THEN 'MAX' ELSE CAST(C.max_length AS VARCHAR) END AS 'MaxLength',
C.precision AS 'Precision',
C.scale AS 'Scale',
CASE
WHEN [XType] IN (34,35,36,40,48,52,56,58,59,60,61,62,98,99,104,122,127,189,240,241) THEN QUOTENAME(C.name) +'  '+ UPPER(T.name) +',' 
WHEN [XType] IN (106,108) THEN QUOTENAME(C.name) +'  '+ UPPER(T.name) +'('+ CAST([Precision] AS VARCHAR) +','+ CAST(C.scale AS VARCHAR) +'),'
WHEN [XType] IN (41,42,43,165,167,173,175,231,239) THEN QUOTENAME(C.name) +'  '+ UPPER(T.name) +'('+ CASE WHEN C.max_length < 0 THEN 'MAX'  WHEN C.max_length > 1 THEN CAST(C.max_length / 2 AS VARCHAR) ELSE CAST(C.max_length AS VARCHAR) END +'),' ELSE NULL END AS 'ColumnList'
FROM sys.all_columns AS C
JOIN systypes AS T ON C.system_type_id = T.xusertype
WHERE C.object_id = (SELECT * FROM @PObjectID)  --373576369

--Return column names and data types
INSERT @Data
SELECT 'CREATE TABLE #ColumnsList ('

INSERT @Data
SELECT 
CASE WHEN C.RowNo = (SELECT MAX(RowNo) FROM @PObjectDetails) THEN LEFT(C.ColumnList, ABS(LEN(C.ColumnList + ',') - 2)) ELSE C.ColumnList END AS 'GeneratedColumns'     
FROM @PObjectDetails AS C

INSERT @Data
SELECT ')'

RETURN
END
GO

一旦提交到数据库，就可以像这样运行它：

SELECT * FROM [dbo].[fnDiscoverColumns] ('ExecutionLogStorage') --name of table

这应该给你这样的输出：

CREATE TABLE #ColumnsList (
[LogEntryId]  BIGINT,
[InstanceName]  NVARCHAR(38),
[ReportID]  UNIQUEIDENTIFIER,
[UserName]  NVARCHAR(260),
[ExecutionId]  NVARCHAR(64),
[RequestType]  TINYINT,
[Format]  NVARCHAR(26),
[Parameters]  NTEXT,
[ReportAction]  TINYINT,
[TimeStart]  DATETIME,
[TimeEnd]  DATETIME,
[TimeDataRetrieval]  INT,
[TimeProcessing]  INT,
[TimeRendering]  INT,
[Source]  TINYINT,
[Status]  NVARCHAR(40),
[ByteCount]  BIGINT,
[RowCount]  BIGINT,
[AdditionalInfo]  XML
)

如何通过脚本自动生成临时表列和数据类型

3 个答案: