<mat-form-field [formGroup]="formGroup">
    <mat-label>{{ join.name }}</mat-label>
    <mat-select
        [title]="join.name"
        [formControlName]="join.name"
        >
        <mat-option
            *ngFor='let choice of choices'
            [value]="choice['id']"
            >
            {{ choice['name'] }}
        </mat-option>
    </mat-select>
</mat-form-field>
