Merge Queries

Had a requirement where two Queries created using the dynamics query framework classes, had to be merged together. My business case was as follows.

Business Case: Required to create a report which would be run for a selected no of employees (query1). Within this selected set of employee certain data was required for a further finer selection of employees ( query2). The query2 was a subset of employee like managers and part time employees with the selected query1.

It was required that the Query2 is appended to the original Query1 and the filters are copied so that the results can be achieved.

if ( filterQuery != null )
{
    //start by looping for all the datasources in the source query and find the common datasource in target query
    //if a common datasource is found, then merge the ranges. If not found try to find the parent if a common parent
    //is found then add the datasource below the right parent and merge the ranges         

    for (int ctr = 1; ctr <= filterQuery.dataSourceCount(); ctr ++)
    {
//check if a common datasource/table exists between the two queries
qdbCurrentSource = filterQuery.dataSourceNo(ctr);
qdbCommon = finalQuery.dataSourceTable(qdbCurrentSource.table());

if (!qdbCommon) //if a common table is not found then look for a parent
{
    parentTable = qdbCurrentSource.parentDataSource().file();

    if (parentTable)
    {
qdbCommonParent = finalQuery.dataSourceTable(parentTable);
if (qdbCommonParent) //if the parent is found then add the current datasource to the common parent
{
    qdbCommon = qdbCommonParent.addDataSource(qdbCurrentSource.table());
    qdbCommon.fetchMode(QueryFetchMode::One2One); //IMPORTANT without this the query can get seperated
 
    for( int intLinkCtr=1; intLinkCtr<= filterQuery.dataSourceNo(ctr).linkCount(); intLinkCtr ++)
    {
link = filterQuery.dataSourceNo(ctr).link(intLinkCtr) ;
if ( link.relatedField() == 0)
{
    qdbCommon.relations(true); //this only works between the parent and current datasource
}
else
{
    qdbCommon.joinMode( filterQuery.dataSourceNo(ctr).joinMode() );
    qdbCommon.addLink( link.field(), link.relatedField() );
}
    } //link counter

    SysQuery::mergeRanges(finalQuery, filterQuery, ctr, false, true);
    SysQuery::mergeFilters( filterQuery, finalQuery,ctr,true,false);
} //common parent
    }
 
    if (!qdbCommon)
    {
qdbCommon = finalQuery.addDataSource(filterQuery.dataSourceNo(ctr).table());                     
qdbCommon.relations(true);
    }
 
}
else
{
    SysQuery::mergeRanges(finalQuery, filterQuery, ctr, false, true);
    SysQuery::mergeFilters( filterQuery, finalQuery,ctr,true,false);
}
    }

    SysQuery::copyDynalinks(finalQuery,filterQuery);
} //filterQuery is null