如何使用 sql 联合或组合某些列而不是其他列

Posted 2023-03-31

【中文标题】如何使用 sql 联合或组合某些列而不是其他列

【英文标题】：How can I union or combine some columns and not others using sql

【发布时间】：2017-11-17 00:01:55

【问题描述】：

我有以下单独的报告需要合并：

--REPORT #1
select o.orderid, o.orderdate, o.shippeddate, od.itemcode, od.itemdescription, od.quantity from orders o
join orderdetails od on od.orderid=o.orderid
where o.orderdate between '01-OCT-2017' and '01-NOV-2017' 
and o.shippeddate  between '01-NOV-2017' and '17-NOV-2017' 
and o.warehouseid=1 
and o.ordertypeid not in (7,8)
and o.orderstatusid in (7,8,9)

--REPORT #2
select o.orderid, o.orderdate, o.shippeddate, od.itemcode, od.itemdescription, od.quantity from orders o
join orderdetails od on od.orderid=o.orderid
where o.orderdate between '01-OCT-2017' and '01-NOV-2017' 
and o.shippeddate  between '01-OCT-2017' and '01-NOV-2017' 
and o.warehouseid=1 
and o.ordertypeid not in (7,8)
and o.orderstatusid in (7,8,9)

--REPORT #3
select o.orderid, o.orderdate, o.shippeddate, od.itemcode, od.itemdescription, od.quantity from orders o
join orderdetails od on od.orderid=o.orderid
where o.orderdate between '01-OCT-2017' and '01-NOV-2017'
and o.shippeddate >='01-NOV-2017'  
and o.warehouseid=1 
and o.ordertypeid not in (7,8)
and o.orderstatusid in (7,8,9)

--REPORT #4
select o.orderid, o.orderdate, o.shippeddate, od.itemcode, od.itemdescription, od.quantity from orders o
join orderdetails od on od.orderid=o.orderid
where o.orderdate between '01-OCT-2017' and '01-NOV-2017' 
and o.shippeddate is null
and o.warehouseid=1 
and o.ordertypeid not in (7,8)
and o.orderstatusid in (7,8,9)

我需要合并这些报告，以便将它们作为一个查询运行。我遇到的问题是每个报告的数量列需要分开，并且使用 UNION 将它们结合起来。每个单独的报告可能没有任何共同的结果，因此连接不起作用。所以最终结果会是这样的：

orderid, orderdate, shippingdate, itemcode, itemdescription, QuanitityA, QuantityB, QuantityC, QuantityD

【问题讨论】：

尽管有您的陈述，但仍有共同的行。如果订单日期在 10 月，并且在 11 月 1 日发货，则该行将出现在前三个报告中。报告 1 和 3 肯定会有重复。你没看到这个是偶然的吗？

【参考方案1】：

OR 不做你想做的事吗？

select o.orderid, o.orderdate, o.shippeddate, od.itemcode,
       od.itemdescription, od.quantity
from orders o join
     orderdetails od 
     on od.orderid = o.orderid
where o.orderdate between '01-OCT-2017' and '01-NOV-2017' and
      (o.shippeddate between '01-NOV-2017' and '17-NOV-2017' or 
       o.shippeddate between '01-OCT-2017' and '01-NOV-2017' or
       o.shippeddate >= '01-NOV-2017' or
       o.shippeddate is null
      ) and
      o.warehouseid = 1 and
      o.ordertypeid not in (7, 8) and
      o.orderstatusid in (7, 8, 9);

假设shippeddate 总是大于orderdate（或NULL），那么您可以删除这些条件。我还建议使用标准日期格式：

select o.orderid, o.orderdate, o.shippeddate, od.itemcode,
       od.itemdescription, od.quantity
from orders o join
     orderdetails od 
     on od.orderid = o.orderid
where o.orderdate between '2017-10-01' and '2017-11-01' and
      ) and
      o.warehouseid = 1 and
      o.ordertypeid not in (7, 8) and
      o.orderstatusid in (7, 8, 9);

【参考方案2】：

我会对常用列（orderid、orderdate、shipdeddate、itemcode、itemdescription）进行选择区分，然后开始对您的每个查询进行左连接。

【参考方案3】：

IS this what you want?
    select o.orderid
    , o.orderdate
    , o.shippeddate
    , od.itemcode
    , od.itemdescription
    , od.quantity AS QuantityA
    , NULL AS QuantityB
    , NULL AS QuantityC
    , NULL AS QuantityD
    from orders o
    join orderdetails od on od.orderid=o.orderid
    where o.orderdate between '01-OCT-2017' and '01-NOV-2017' 
    and o.shippeddate  between '01-NOV-2017' and '17-NOV-2017' 
    and o.warehouseid=1 
    and o.ordertypeid not in (7,8)
    and o.orderstatusid in (7,8,9)
    UNION
    select o.orderid
    , o.orderdate
    , o.shippeddate
    , od.itemcode
    , od.itemdescription
    , NULL AS QuantityA
    , od.quantity AS QuantityB
    , NULL AS QuantityC
    , NULL AS QuantityD 
    from orders o
    join orderdetails od on od.orderid=o.orderid
    where o.orderdate between '01-OCT-2017' and '01-NOV-2017' 
    and o.shippeddate  between '01-OCT-2017' and '01-NOV-2017' 
    and o.warehouseid=1 
    and o.ordertypeid not in (7,8)
    and o.orderstatusid in (7,8,9)
    UNION
    select o.orderid
    , o.orderdate
    , o.shippeddate
    , od.itemcode
    , od.itemdescription
    , NULL AS QuantityA
    , NULL AS QuantityB
    , od.quantity AS QuantityC
    , NULL AS QuantityD
    from orders o
    join orderdetails od on od.orderid=o.orderid
    where o.orderdate between '01-OCT-2017' and '01-NOV-2017'
    and o.shippeddate >='01-NOV-2017'  
    and o.warehouseid=1 
    and o.ordertypeid not in (7,8)
    and o.orderstatusid in (7,8,9)
    UNION
    select o.orderid
    , o.orderdate
    , o.shippeddate
    , od.itemcode
    , od.itemdescription
    , NULL AS QuantityA
    , NULL AS QuantityB
    , NULL AS QuantityC
    , od.quantity AS QuantityD
    from orders o
    join orderdetails od on od.orderid=o.orderid
    where o.orderdate between '01-OCT-2017' and '01-NOV-2017' 
    and o.shippeddate is null
    and o.warehouseid=1 
    and o.ordertypeid not in (7,8)
    and o.orderstatusid in (7,8,9)