SQL嵌套子查询引用祖父母列

I have a particularly complicated query for a report. It selects several columns from a view, and it must build a column via aggregately concatenating several fields. To complicate things further, the concatenation must contain 3 fields even if there are 0 in reality (The concatenation is comma delimited, so empty fields will still be noticed).I have a particularly complicated query for a r