Question

我有4种不同的选择状态，它们将结果组合在一起并显示如此命令。

lab_orders              MED111
lab_orders              MED262383
mg_orders               MED262383
mg_orders               UNT222
pcg_pharmacogenetics    MED262371
pcg_pharmacogenetics    UNT248234
well_wellness           UST601061
well_wellness           UNTAccession
well_wellness           UST333

使用此查询。

select 'mg_orders',csv as csv1
from (select csv from csvdata where csv not in(select orderid from mg_orders)) as t1
union
select 'lab_orders',csv as csv2
from (select csv from csvdata where csv not in(select orderid from lab_orders)) as t2
union
select 'pcg_pharmacogenetics',csv as csv3
from (select csv from csvdata where csv not in(select orderid from pcg_pharmacogenetics)) as t3
union
select 'well_wellness',csv as csv4
from (select csv from csvdata where csv not in(select orderid from well_wellness)) as t4

我想要做的是将结果集返回到不同的列中，我尝试了以下但是得到了＃34;没有列名为csv2＆＃34;

select csv1, csv2, csv3, csv4
from(
select 'mg_orders',csv as csv1
from (select csv from csvdata where csv not in(select orderid from mg_orders)) as t1
union
select 'lab_orders',csv as csv2
from (select csv from csvdata where csv not in(select orderid from lab_orders)) as t2
union
select 'pcg_pharmacogenetics',csv as csv3
from (select csv from csvdata where csv not in(select orderid from pcg_pharmacogenetics)) as t3
union
select 'well_wellness',csv as csv4
from (select csv from csvdata where csv not in(select orderid from well_wellness)) as t4
) as t


   lab_orders       mg_orders     pcg_pharmacogenetics            
   MED111           MED262383     MED262371
   MED262383        UNT222        UNT248234

Answer 1

当您使用union时，第一个查询中的列名或别名将用于结果集。在您的情况下，结果集将包含mg_orders和csv1作为列标题。

我假设您正在寻找类似于

的查询

select 
max(case when csv not in(select orderid from mg_orders) then csv end) as csv1,
max(case when csv not in(select orderid from lab_orders) then csv end) as csv2,
max(case when csv not in(select orderid from pcg_pharmacogenetics) then csv end) as csv3,
max(case when csv not in(select orderid from well_wellness) then csv end) as csv4
from csvdata

将联合查询返回到多个列

1 个答案: