addWhereFindNull method
If value is null then search value IS NULL
Implementation
void addWhereFindNull(String fieldName, Object? value, {int? table_id}) {
if (value == null) {
WhereStruct whereStruct=WhereStruct(table_id, fieldName, SqlOperator.IS, SqlKeyword("NULL"));
_whereStructList.add(whereStruct);
} else {
WhereStruct whereStruct=WhereStruct(table_id, fieldName, SqlOperator.EQUAL, value);
_whereStructList.add(whereStruct);
}
}