This is absolutely possible. Although you shouldn't do it unless you know what you are dealing with.
Took me about 2 days to figure it out.
Here is a stored procedure where i enter:
---database name
(schema name is "_" for readability)
---table name
---column
---column data type
(column added is always null, otherwise you won't be able to insert)
---the position of the new column.
Since I'm working with tables from SAM toolkit (and some of them have > 80 columns) , the typical variable won't be able to contain the query. That forces the need of external file. Now be careful where you store that file and who has access on NTFS and network level.
Cheers!
USE [master]
GO
/****** Object: StoredProcedure [SP_Set].[TrasferDataAtColumnLevel] Script Date: 8/27/2014 2:59:30 PM ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE PROCEDURE [SP_Set].[TrasferDataAtColumnLevel]
(
@database varchar(100),
@table varchar(100),
@column varchar(100),
@position int,
@datatype varchar(20)
)
AS
BEGIN
set nocount on
exec ('
declare @oldC varchar(200), @oldCDataType varchar(200), @oldCLen int,@oldCPos int
create table Test ( dummy int)
declare @columns varchar(max) = ''''
declare @columnVars varchar(max) = ''''
declare @columnsDecl varchar(max) = ''''
declare @printVars varchar(max) = ''''
DECLARE MY_CURSOR CURSOR LOCAL STATIC READ_ONLY FORWARD_ONLY FOR
select column_name, data_type, character_maximum_length, ORDINAL_POSITION from ' + @database + '.INFORMATION_SCHEMA.COLUMNS where table_name = ''' + @table + '''
OPEN MY_CURSOR FETCH NEXT FROM MY_CURSOR INTO @oldC, @oldCDataType, @oldCLen, @oldCPos WHILE @@FETCH_STATUS = 0 BEGIN
if(@oldCPos = ' + @position + ')
begin
exec(''alter table Test add [' + @column + '] ' + @datatype + ' null'')
end
if(@oldCDataType != ''timestamp'')
begin
set @columns += @oldC + '' , ''
set @columnVars += ''@'' + @oldC + '' , ''
if(@oldCLen is null)
begin
if(@oldCDataType != ''uniqueidentifier'')
begin
set @printVars += '' print convert('' + @oldCDataType + '',@'' + @oldC + '')''
set @columnsDecl += ''@'' + @oldC + '' '' + @oldCDataType + '', ''
exec(''alter table Test add ['' + @oldC + ''] '' + @oldCDataType + '' null'')
end
else
begin
set @printVars += '' print convert(varchar(50),@'' + @oldC + '')''
set @columnsDecl += ''@'' + @oldC + '' '' + @oldCDataType + '', ''
exec(''alter table Test add ['' + @oldC + ''] '' + @oldCDataType + '' null'')
end
end
else
begin
if(@oldCLen < 0)
begin
set @oldCLen = 4000
end
set @printVars += '' print @'' + @oldC
set @columnsDecl += ''@'' + @oldC + '' '' + @oldCDataType + ''('' + convert(character,@oldCLen) + '') , ''
exec(''alter table Test add ['' + @oldC + ''] '' + @oldCDataType + ''('' + @oldCLen + '') null'')
end
end
if exists (select column_name from INFORMATION_SCHEMA.COLUMNS where table_name = ''Test'' and column_name = ''dummy'')
begin
alter table Test drop column dummy
end
FETCH NEXT FROM MY_CURSOR INTO @oldC, @oldCDataType, @oldCLen, @oldCPos END CLOSE MY_CURSOR DEALLOCATE MY_CURSOR
set @columns = reverse(substring(reverse(@columns), charindex('','',reverse(@columns)) +1, len(@columns)))
set @columnVars = reverse(substring(reverse(@columnVars), charindex('','',reverse(@columnVars)) +1, len(@columnVars)))
set @columnsDecl = reverse(substring(reverse(@columnsDecl), charindex('','',reverse(@columnsDecl)) +1, len(@columnsDecl)))
set @columns = replace(replace(REPLACE(@columns, '' '', ''''), char(9) + char(9),'' ''), char(9), '''')
set @columnVars = replace(replace(REPLACE(@columnVars, '' '', ''''), char(9) + char(9),'' ''), char(9), '''')
set @columnsDecl = replace(replace(REPLACE(@columnsDecl, '' '', ''''), char(9) + char(9),'' ''),char(9), '''')
set @printVars = REVERSE(substring(reverse(@printVars), charindex(''+'',reverse(@printVars))+1, len(@printVars)))
create table query (id int identity(1,1), string varchar(max))
insert into query values (''declare '' + @columnsDecl + ''
DECLARE MY_CURSOR CURSOR LOCAL STATIC READ_ONLY FORWARD_ONLY FOR '')
insert into query values (''select '' + @columns + '' from ' + @database + '._.' + @table + ''')
insert into query values (''OPEN MY_CURSOR FETCH NEXT FROM MY_CURSOR INTO '' + @columnVars + '' WHILE @@FETCH_STATUS = 0 BEGIN '')
insert into query values (@printVars )
insert into query values ( '' insert into Test ('')
insert into query values (@columns)
insert into query values ( '') values ( '' + @columnVars + '')'')
insert into query values (''FETCH NEXT FROM MY_CURSOR INTO '' + @columnVars + '' END CLOSE MY_CURSOR DEALLOCATE MY_CURSOR'')
declare @path varchar(100) = ''C:\query.sql''
declare @query varchar(500) = ''bcp "select string from query order by id" queryout '' + @path + '' -t, -c -S '' + @@servername + '' -T''
exec master..xp_cmdshell @query
set @query = ''sqlcmd -S '' + @@servername + '' -i '' + @path
EXEC xp_cmdshell @query
set @query = ''del '' + @path
exec xp_cmdshell @query
drop table ' + @database + '._.' + @table + '
select * into ' + @database + '._.' + @table + ' from Test
drop table query
drop table Test ')
END