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How to exclude one column from select statement?

Posted on 2011-02-18
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Last Modified: 2012-05-11
Have a table with 100 columns and want to show 99 columns. Easy way is
select col1, col2, ...col99
from t1;
That will be multiple pages only for select part. but if doing the following
select * from t1;
That will show everything.
Gurus, Is there any easy way to solve my issue?


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Question by:jl66
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14 Comments
 
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Assisted Solution

by:slightwv (䄆 Netminder)
slightwv (䄆 Netminder) earned 260 total points
ID: 34927472
In sqlplus it's pretty easy:

column col100 noprint

Where are you running the query?
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LVL 14

Expert Comment

by:VBClassicGuy
ID: 34929314
You could either:

1. Select all fields and just ignore the unwanted one in code.

2. Build a view which selects all columns except the unwanted one, and then select from the view rather than the table.
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Author Comment

by:jl66
ID: 34929340
Thank you so much. The point should be awarded to you now. However, the purpose for it is as follows:

create table t2 as
select * from t1;

in t2 it only needs col1....col99. Is there any way to deal with it?
If you need a new ticket, I can open a new one. Sorry for that.

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Author Comment

by:jl66
ID: 34929363
=>Is there any way to deal with it?  It means that "Don't list everything col1,..col99 in select part".
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LVL 76

Accepted Solution

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slightwv (䄆 Netminder) earned 260 total points
ID: 34929380
Selecting in code and create table as select are really two different things.

I don't know of an easy way to do this.

You never did respond to my question:
Where are you running the query?

You can likely 'build' the query dynamically but we need to know your exact requirements.
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LVL 14

Expert Comment

by:VBClassicGuy
ID: 34929435
If you create the view I mentioned, you can use:

CREATE TABLE t2 SELECT * FROM vwT1

(assuming you name your view vwT1)
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LVL 14

Assisted Solution

by:VBClassicGuy
VBClassicGuy earned 100 total points
ID: 34929464
Or, go ahead and use your statement of:

CREATE TABLE t2 AS SELECT * FROM t1

then follow it with this statement:

ALTER TABLE t2 DROP COLUMN MyUndesiredField
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Author Comment

by:jl66
ID: 34931265
If the table has over 100 Millions rows, adding one column and dropping it would be costly. Is there any better way to deal with it
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LVL 15

Expert Comment

by:Aaron Shilo
ID: 34931830
hi

no need to drop the column.
use the UNUSED command

alter table alter column set unused.

this is a Datadict command and works immediatly no overhead.
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LVL 15

Assisted Solution

by:Aaron Shilo
Aaron Shilo earned 140 total points
ID: 34931834
^

just a fix for the command

ALTER TABLE table_name SET UNUSED (column_name);
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LVL 15

Assisted Solution

by:Aaron Shilo
Aaron Shilo earned 140 total points
ID: 34931836
hi

there is another way.

you could generate a dynamic query using  DBA_TAB_COLUMNS
and select the first 99 columns for the dynamic query.
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LVL 1

Expert Comment

by:maheshchari
ID: 34933789
select * from tablename where rownum>=1 and rownum<=99;
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LVL 76

Expert Comment

by:slightwv (䄆 Netminder)
ID: 34934337
What are you wanting to do?

Are you wanting to select columns or remove the column permanently from the table?

ashilo,

I already mentioned dynamic sql but thanks for providing the view.
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Author Closing Comment

by:jl66
ID: 34934876
Thank for everyone. Dynamically build the query may be the practical way to work out the issue. Special thanks to slightwv and ashilo. It does not seem matter. I can use dba_tab_columns or user_..., depending on the user privilege logged in to form the query.
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