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(Unknown
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(Unknown
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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