add new column in the middle of a table - sybase 11.9.2

Is it possible to add a new column where ever we want in a existing table. If so How ?

thanks,

hmk
hmkAsked:
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moduloConnect With a Mentor Commented:
PAQ'd and 100 points refunded

modulo

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amitpagarwalCommented:
i can think of the following approach :

suppose the table has the following struction

Create table OLD ( a int , b int , c int )

Now you want to insert a new column after b - say it is d int datatype.

I would say select a , b , d = 0, c into #x from OLD

drop table OLD
select * into OLD from #x
drop table #x

Thanks.
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hmkAuthor Commented:
Yes if you are using temp tables that's ok but I am talking about permanent tables which I can't drop and recreate. I just want to modify existing table. Can we use alter table ? if so how ?

hmk
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amitpagarwalCommented:
The problem with alter table is that it will add a column at the end of the table - which I guess may not fulfill your requirement ( you want to add a column anywhere you like ? ) - so i guess you need to create a new table and drop the old one ..

Thanks.
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bretCommented:
In 11.9.2, you would have to create a new table with the
desired column layout and move the data to the new table
(as in the SELECT INTO technique discussed earlier [note that using temp tables like that is dangerous, where would you be if there was a power failure right after "drop table", while the data thus only existed in the temp table?]).


However, 11.9.2 is an obsolete, end-of-lifed version of ASE.  Current versions support more options with ALTER TABLE, such that you could do something like this:

create table mytable (a int, b int)
go
alter table mytable add newcol int default 2, b2 int default 3)
go

-- At this point you have a table (a,b,newcol,b2)

update mytable set b2 = b
go
alter table mytable drop b
go
sp_rename "mytable.b2", "b"
go

-- At this point you have a table with the columns in the desired default order of (a,newcol,b)


 


 
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hmkAuthor Commented:
It's excellent idea. But i have a problem while doing this.
I was testing this in tempdb  by creating a table and I am getting error "incorrect syntax near the keyword DROP"

My original table structure is like this
OldTable (a int,b int, c char(12))

And I want oldtable to look like this
NewTable (a int,b int,newcolumn int, c char(12))

I created the table  tempdb..NewTable same as OldTable structure. executed following statements to change the table structure.

alter tempdb..NewTable
add newcolumn decimal(13,8) null,c1 char(12) null

update tempdb..NewTable
set c1 = c

untill now it works fine but while executing following statement i am getting error. I don't find any syntax errors in the statement. And I have a question for you , what if the field(c) has index on it. Do we need to drop index first and then column(c).And also do we need to recreate the index on the field(c1) before rename it.

alter tempdb..NewTable drop c

Please reply.
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bretCommented:
try "alter table tempdb..NewTable drop c"

-bret
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hmkAuthor Commented:
I tried Still same problem.


hmk
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hmkAuthor Commented:
bret,

I found this on sybase site.
alter table drop column is an unsupported command in release 11.9.2 and earlier, with possible dangerous outcomes.
Hers is the link.

http://www.sybase.com/detail/1,6904,671,00.html



hmk
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hmkAuthor Commented:
I tried Still same problem.


hmk
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hmkAuthor Commented:
The only way is to use insert data into a #table and load from it into new table.
This I know it So I am going to delete this question.

Thanks for sharing your ideas.

hmk.
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