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From Pavel Bortnovskiy <pbortnovs...@jefferies.com>
Subject RE: setting column to NULL
Date Wed, 20 Jun 2012 17:13:00 GMT
Thank you so much, Rick, for your prompt response - it's very helpful.

It actually makes a lot of sense, esp. for my application.

Respectfully,
Pavel.

-----Original Message-----
From: Rick Hillegas [mailto:rick.hillegas@oracle.com]
Sent: Wednesday, June 20, 2012 1:10 PM
To: derby-user@db.apache.org
Subject: Re: setting column to NULL

On 6/20/12 9:55 AM, Pavel Bortnovskiy wrote:
>
> Hello,
>
> It seems that running the following SQL statement results in an error
> in Derby, while it's working fine in other DBs (such as Oracle or Sybase):
>
> select
>
> a as "ColumnA",
>
> null as "ColumnB"
>
> from SomeTable
>
> java.sql.SQLSyntaxErrorException: Syntax error: Encountered "null" at
> line 10, column 2.
>
> at
> org.apache.derby.impl.jdbc.SQLExceptionFactory40.getSQLException(Unkno
> wn
> Source)
>
> at org.apache.derby.impl.jdbc.Util.generateCsSQLException(Unknown
> Source)
>
> at
> org.apache.derby.impl.jdbc.TransactionResourceImpl.wrapInSQLException(
> Unknown
> Source)
>
> at
> org.apache.derby.impl.jdbc.TransactionResourceImpl.handleException(Unk
> nown
> Source)
>
> at org.apache.derby.impl.jdbc.EmbedConnection.handleException(Unknown
> Source)
>
> at org.apache.derby.impl.jdbc.ConnectionChild.handleException(Unknown
> Source)
>
> at org.apache.derby.impl.jdbc.EmbedPreparedStatement.<init>(Unknown
> Source)
>
> at org.apache.derby.impl.jdbc.EmbedPreparedStatement20.<init>(Unknown
> Source)
>
> at org.apache.derby.impl.jdbc.EmbedPreparedStatement30.<init>(Unknown
> Source)
>
> at org.apache.derby.impl.jdbc.EmbedPreparedStatement40.<init>(Unknown
> Source)
>
> at org.apache.derby.jdbc.Driver40.newEmbedPreparedStatement(Unknown
> Source)
>
> at org.apache.derby.impl.jdbc.EmbedConnection.prepareStatement(Unknown
> Source)
>
> at org.apache.derby.impl.jdbc.EmbedConnection.prepareStatement(Unknown
> Source)
>
> Is this by design? And is there a work-around? What needs to be done
> to set a column to null?
>
Hi Pavel,

Derby does not have a default datatype for untyped nulls. You need to use a cast clause in
order to give the null a type. Here's an example:

connect 'jdbc:derby:memory:db;create=true';

create table t( a int );
insert into t( a ) values ( 1 );

-- untyped null fails
select null as b from t;

-- typed null succeeds
select cast( null as int ) as b from t;

Hope this helps,
-Rick
>
> Thank you,
>
> Pavel.
>
>
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or otherwise use it or any part of it in any form whatsoever. This email may be produced at
the request of regulators or in connection with civil litigation. Jefferies accepts no liability
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Limited; registered in England: no. 1978621; registered office: Vintners Place, 68 Upper Thames
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