How to add another DataSource in prompt Query?

I want to add another data source in Query prompt.

when I launch a form I open the prompt Query.

In my Form init method I have :

QueryRun queryRun;

super();

queryRun = new QueryRun(TableA_ds.query());
if (! queryRun.prompt())
{
     element.close();
}

TableA_ds.query(queryRun.query());

In my Form datasource, in init method, I have putted this code to set my query range:

tableA_ds.query().dataSourceTable(tablenum(TableA)).addRange(fieldnum(TableA,FieldtableA)).value(SysQuery::valueUnlimited() );

I want to add another data source (another Table) TableB . I used this code:

purchLine_ds.query().dataSourceTable(tablenum(TableB)).addRange(fieldnum(TableA,FieldtableB)).value(SysQuery::valueUnlimited() );

But when I launch a Form I view anly record query range form TableA

TableA and TableB are relations with a field : PurchId. I want to see two range.can help me, Thanks for your time,

enjoy!