您需要string_agg如下:
Select company_name, seller,
String_agg(investor, ',') within group (order by investor) as investor,
Date
From (your_query) t
Group by company_name, seller, date;
使用STUFF
SELECT companyname,seller,STUFF((SELECT CONCAT(',' ,Investor)
FROM table t1
WHERE t1.companyname = t2.companyname
AND t1.seller=t2.seller
FOR XML PATH ('')), 1, 1, '') AS Investor,date
From table t2