Question

我对为什么我的结果在Project_ID中显示null感到困惑。我看了下面的帖子并尝试了inner join，但结果是徒劳的，与left join相同。我只有两个不同的Project_ID。出于某种奇怪的原因，Name将再次使用之前列表中添加的Count进行说明。为什么这样做，我该如何解决这个问题？请提供您的建议。

Why does my SQL query return rows with NULL? It should never return rows with NULL

select dp."Name",count(dp."Name") Count,max(to_char(ft."Hours",'9,999')) "Maximum Hours Worked",
max(ft."Salary"::money) "Maximum Salary",
ft."Project_ID"
from facttable ft
left join alldatainput dp on dp."alldatainputpk" = ft."alldatainputfk"
group by rollup(dp."Name",ft."Project_ID")

结果：

       Name             Count    Maximum Hours Worked  Maximum Salary  Project_ID
Hulk Hogan              157           3,500             $432,995.00     LFC
Hulk Hogan              43            3,499             $550,000.00     PCR
Hulk Hogan              200           3,500             $550,000.00   (null)
Andre the Giant         42            5,300             $870,000.00     PCR
Andre the Giant         42            5,300             $870,000.00   (null)
Bret Hart                5            3,675             $512,000.00     LFC
Bret Hart               10            4,193             $716,510.00     PCR
Bret Hart               15            4,193             $716,510.00   (null)
Winnie the Pooh         561           5,600             $929,654.00     PCR
Winnie the Pooh         561           5,600             $929,654.00   (null)
                        1000          5,600             $929,654.00   (null)

Answer 1

Grouping Sets

select
    dp.Name,count(dp."Name") Count,
    max(to_char(ft."Hours",'9,999')) "Maximum Hours Worked",
    max(ft."Salary"::money) "Maximum Salary",
    ft."Project_ID"
from
    facttable ft
    left join
    alldatainput dp on dp."alldatainputpk" = ft."alldatainputfk"
group by grouping sets ((dp."Name",ft."Project_ID"), ())

为什么我的SQL语法显示为null？

1 个答案: