有没有办法在 IBM DB2 环境中实现这一点

Question

在 DB2 中有没有办法基本上说：

当 sku (select * from table1 where tb1field = 'SMOMD') 然后 'True' 结束时的情况

好的，到目前为止，这是我的查询，我已经为此至少一个月了，所以任何帮助都会很棒。

select tb4.customer, tb4.sku, tb4.qty, tb4.retqty, tb4.stipqty, tb4.lastdate, tb4.firstdate, tb4.stipdate

from(
--Table 4
select tb3.Customer as Customer, tb3.sku as SKU, tb3.qty as Qty, tb3.retqty as RetQty, tb3.stipqty as STIPQty,
case when tb3.lastdate is null then '00/0000' else substr(tb3.lastdate,5,2)||'/'||substr(tb3.lastdate,1,4) end as LastDate,
case when tb3.firstdate is null then '00/0000' else substr(tb3.firstdate,5,2)||'/'||substr(tb3.firstdate,1,4) end as FirstDate,
case when tb3.stipdate is null then '00/0000' else substr(tb3.stipdate,5,2)||'/'||substr(tb3.stipdate,1,4) end as STIPDate

from(
--Table 3
select tb2.Customer as Customer, tb2.SKU as SKU, tb2.Qty as Qty, tb2.RetQty as RetQty, tb2.STIPQty as STIPQty,
max(case when tb2.TranID in ('010','100') then tb2.datenum end) as LastDate,
min(case when tb2.TranID in ('010','100') then tb2.datenum end) as FirstDate,
case when tb2.RC = '4M' then tb2.datenum end as STIPDate

from(
--Table 2
select tb1.Customer as Customer, tb1.SKU as SKU,
sum(case when tb1.TranID in ('010','100') then abs(tb1.OrdNet) else '0' end) as Qty,
sum(case when tb1.TranID = '500' and tb1.rc != '4M' then abs(tb1.OrdNet) else '0' end) as RetQty,
count(case when tb1.rc = '4M' then tb1.sku end) as STIPQty,
tb1.datenum as datenum, tb1.TranID as tranid, tb1.RC as rc

from(
--Table 1
select distinct stkund as Customer, sthptg||space(1)||stmodl||space(1)||stvari||space(1)||stfarb||space(1)||stgroe as SKU, 
stvorg as TranID, stggru as RC, stprg09 as PG9, stprg08 as PG8, stperi as datenum, ormne1 as OrdNet
from st_usus.s_stati_pv
join caspdtau.cospf440 on stadrn = jadr40
where trim(stvert) in ('111S','122S')
and sthptg != 'V'
and aktv40 = 'A'
and stprg01 in ('01','04')
and stprg02 = '01'
and stvorg in ('500','010','100')
and stperi >= '20160100'

) as tb1
group by tb1.Customer, tb1.SKU, tb1.datenum, tb1.tranid, tb1.rc


) as tb2
group by tb2.customer, tb2.sku, tb2.qty, tb2.retqty, tb2.stipqty, tb2.tranid, tb2.rc, tb2.datenum

) as tb3
group by tb3.customer, tb3.sku, tb3.qty, tb3.retqty, tb3.stipqty, tb3.lastdate, tb3.firstdate, tb3.stipdate

) as tb4
order by tb4.Customer, tb4.sku

Answer 1

我不会试图准确地解读你想要做什么......

一些一般性建议，而不是使用嵌套表表达式 (NTE)

select <..> from (select <...>from mytable)

考虑公用表表达式 (CTE)

with 
  table1 as (select <...> from st_usus.s_stati_pv join caspdtau.cospf440 on stadrn = jadr40)
, table2 as (select <...> from table1)
, table3 as (select <...> from table2)
, table4 as (select <....> from table3)
select <...> from table4;

每个 CTE（即 tableX）可以根据需要引用先前的 CTE 或物理表/视图。最终选择可以引用一个或多个 CTE 以及一个或多个物理表或视图。

使用 CTE 构建的好处是，您可以在每一步之后检查您的结果..

with 
  table1 as (select <...> from st_usus.s_stati_pv join caspdtau.cospf440 on stadrn = jadr40)
select * from table1;