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