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.hille...@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.(Unknown
> Source)
>
> at org.apache.derby.impl.jdbc.EmbedPreparedStatement20.(Unknown
> Source)
>
> at org.apache.derby.impl.jdbc.EmbedPreparedStatement30.(Unknown
> Source)
>
> at org.apache.derby.impl.jdbc.EmbedPreparedStatement40.(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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