Question

我在excel中有一个列表，我试图填充数据库中的数据。我需要按照查询中列出的顺序提取数据，因此我使用UNION ALL来执行此操作。

但是，union＆quot; ed选项中的某些记录是空的，因此结果集中的行号变得混乱。对不起，查询有点复杂，我不能使它更简单

select * from (select top 1 fundid as fundid, fundname, effectivedate from fundnamehist where fundID = '83' order by effectivedate desc) as tbl2
union all select * from (select top 1 fundid as fundid, fundname, effectivedate from fundnamehist where fundID = '173' order by effectivedate desc) as tbl3

... --a few hundred lines like the one above, generated in excel

因此，在此示例中，如果FundID 173的内部选择结果返回没有结果，我只会得到一个而不是两个结果。相反，我希望它返回某些内容，就像0, "", 1900-1-1之类的行而不是任何内容。我的总查询比我想要的短约400行。

我该怎么做？

我尝试在＆＃34;内部＆＃34;中添加ISNULL() s。选择和＆＃34;外部＆＃34;选择，但那不起作用。

＆＃34;内＆＃34;选择ISNULL s

select * from (select top 1 isnull(fundid,0) as fundid, isnull(fundname,'') as fundname, isnull(effectivedate, '1900-1-1') as effectivedate from fundnamehist where fundID = '83' order by effectivedate desc) as tbl2

＆＃34;外＆＃34;选择ISNULL s

select isnull(fundid,0) as fundid, isnull(fundname,'') as fundname, isnull(effectivedate, '1900-1-1') as effectivedate from (select top 1 fundid, fundname, effectivedate from fundnamehist where fundID = '83' order by effectivedate desc) as tbl2

（请注意，这是一次性过程，我并不是真的在寻找任何类型的优化）

Answer 1

从这个答案中找到答案：https://dba.stackexchange.com/a/41068/35665

有点乏味，但我不得不在子查询中做另一个UNION ALL：

...
union all 
    select  fundid, fundname, effectivedate from 
        (select top 1 fundid, fundname, effectivedate from fundnamehist where fundID = '173' order by effectivedate desc 
            union all select null,null,'1900-1-1' 
            where not exists 
            (select top 1 fundid as fundid, fundname, effectivedate from fundnamehist where fundID = '173')
        ) as tbl3

SQL Union如果为null，则返回“空白”记录

1 个答案: