How to select Distinct Using X++?

How to select distinct in X++ when actually there is no reserved word like this in X++ for this we do work around to solve this problem .

this example to retrieve distinct account from the lockup table to show it :

public void lookup(FormControl _formControl, str _filterStr)
{
    SysTableLookup       sysTableLookup =   SysTableLookup::newParameters(tablenum(MBSR_ACC_PATIENTS), _formControl);
    Query                query = new Query();
    QueryBuildDataSource queryBuildDataSource;
    ;
    sysTableLookup.addLookupfield(fieldnum(MBSR_ACC_PATIENTS, ACCOUNT_NO));
    sysTableLookup.addLookupfield(fieldnum(MBSR_ACC_PATIENTS, ACCOUNT_NM));
    queryBuildDataSource = query.addDataSource(tablenum(MBSR_ACC_PATIENTS));
    queryBuildDataSource.addSortField(fieldnum(MBSR_ACC_PATIENTS, ACCOUNT_NO));
    queryBuildDataSource.addSortField(fieldnum(MBSR_ACC_PATIENTS, ACCOUNT_NM));
    queryBuildDataSource.orderMode(ordermode::GroupBy);
    sysTableLookup.parmQuery(query);
    sysTableLookup.performFormLookup();

    super(_formControl, _filterStr);
}

This three lines of code with yellow color are the work around to solve the distinct problem