db-derby-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Bernd Ruehlicke (JIRA)" <derby-...@db.apache.org>
Subject [jira] Commented: (DERBY-147) ERROR 42X79 not consistant ? - same column name specified twice
Date Fri, 21 Jul 2006 19:57:15 GMT
    [ http://issues.apache.org/jira/browse/DERBY-147?page=comments#action_12422761 ] 
            
Bernd Ruehlicke commented on DERBY-147:
---------------------------------------

OK got it perfectly working now. 

I also refactored the getOrderByColumn(String, TableName) to call the getOrderByColumn(String,
TableName, int) instead of double the code. (See code below)

After I have figured out why the source is distorted when I check it out with svn I will apply
the diff and make a patch. (That's I guess is why my fist patch had so many spaces ...)


ij>  select col1, col2, col1 from t order by col1;
COL1       |COL2      |COL1
----------------------------------
1          |one       |1
2          |two       |2
3          |three     |3

3 rows selected
ij>  select col1, col2, col1 from t order by col1, col2;
COL1       |COL2      |COL1
----------------------------------
1          |one       |1
2          |two       |2
3          |three     |3

3 rows selected
ij>  select col1, col2, col1, col1, col1, col2, col2 from t order by col1;
COL1       |COL2      |COL1       |COL1       |COL1       |COL2      |COL2
--------------------------------------------------------------------------------
1          |one       |1          |1          |1          |one       |one
2          |two       |2          |2          |2          |two       |two
3          |three     |3          |3          |3          |three     |three

3 rows selected



Codechange in  ./engine/org/apache/derby/impl/sql/compile/ResultColumnList.java


        /**
         * For order by, get a ResultColumn that matches the specified
         * columnName 
         *
         * @param columnName	The ResultColumn to get from the list
         * @param tableName	The table name on the OrderByColumn, if any
         * @param tableNumber	The tableNumber corresponding to the FromTable with the
         *			exposed name of tableName, if tableName != null.
         *
         * @return	the column that matches that name.
         */
        public ResultColumn getOrderByColumn(String columnName, TableName tableName, int tableNumber)
        throws StandardException
        {
            int size = size();
            ResultColumn retVal = null, resultColumn;
            
            for (int index = 0; index < size; index++)
            {
                resultColumn = (ResultColumn) elementAt(index);
                
                /* The order by column is qualified, then it is okay to consider
                 * this RC if:
                 *	o  The RC is qualified and the qualifiers on the order by column
                 *	   and the RC are equal().
                 *	o  The RC is not qualified, but its expression is a ColumnReference
                 *	   from the same table (as determined by the tableNumbers).
                 */
                if (tableName != null)
                {
                    ValueNode rcExpr = resultColumn.getExpression();
                    if (rcExpr == null || !(rcExpr instanceof ColumnReference))
                        continue;
                    
                    ColumnReference cr = (ColumnReference) rcExpr;
                    if( (! tableName.equals( cr.getTableNameNode())) && tableNumber
!= cr.getTableNumber())
                        continue;
                }
                
                /* We finally got past the qualifiers, now see if the column
                 * names are equal.
                 */
                if (columnName.equals( resultColumn.getName()) )
                {
                    if (retVal == null)
                    {
                        retVal = resultColumn;
                    }
                    else if (index >= size - orderBySelect)
                    {// remove the column due to pullup of orderby item
                        removeElement(resultColumn);
                        decOrderBySelect();
                        break;
                    }
                }
            }
            return retVal;
        }


	/**
	 * For order by, get a ResultColumn that matches the specified 
	 * columnName
	 *
	 * @param columnName	The ResultColumn to get from the list
	 * @param tableName	The table name on the OrderByColumn, if any
	 *
	 * @return	the column that matches that name.
	 */
	public ResultColumn getOrderByColumn(String columnName, TableName tableName)
		throws StandardException
	{
            return getOrderByColumn(columnName, tableName, -1);
	}





> ERROR 42X79 not consistant ? - same column name specified twice
> ---------------------------------------------------------------
>
>                 Key: DERBY-147
>                 URL: http://issues.apache.org/jira/browse/DERBY-147
>             Project: Derby
>          Issue Type: Bug
>          Components: SQL
>            Reporter: Bernd Ruehlicke
>         Attachments: derby-147-10.0.2.1.diff, derby-147.diff
>
>
> This happens from JDBC or ij. Here the output form ij>
> ij version 10.0 
> CONNECTION0* - 	jdbc:derby:phsDB 
> * = current connection 
> ij> select a1.XXX_foreign, a1.native, a1.kind, a1.XXX_foreign FROM slg_name_lookup
a1 ORDER BY a1.XXX_foreign;
> ERROR 42X79: Column name 'XXX_FOREIGN' appears more than once in the result of the query
expression. 
> But when removing the ORDER BY and keeping the 2 same column names it works
> ij> select a1.XXX_foreign, a1.native, a1.kind, a1.XXX_foreign FROM slg_name_lookup
a1;
> XXX_FOREIGN                                                                     |NATIVE
                                                                         |KIND           
                        |XXX_FOREIGN                                                     
                -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 
> 0 rows selected 
> ij> 
> So - it seams to be OK to specify the same column twice - as long as you do not add the
ORDER BY clause.  
> I woul dof course like that the system allows this - but at leats it should be consistant
and either allow both or none of the two queries above.

-- 
This message is automatically generated by JIRA.
-
If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa
-
For more information on JIRA, see: http://www.atlassian.com/software/jira

        

Mime
View raw message