如何在SQL中使用带多个条件的嵌套大小写

如何修改下面的sql脚本以计算以下条件

• 如果LPO为空或不为空，则在2018年1月1日至2018年3月31日之间的发行日期，总含税将为数量x单价加5%

• 2018年3月31日之后，当LPO不为空时，数量x单价不应增加5%，否则增加5%
  它如何处理嵌套的case或建议任何其他方式

我的桌子：

+------------+-----+------------+---------------+
| Issue_date | qty | unit_price |      LPO      |
+------------+-----+------------+---------------+
| 10-Jan-18  |   1 |         42 | 1-2018-001166 |
| 12-Jan-18  |   1 |        100 | NULL          |
| 20-Sep-18  |   1 |         25 | NULL          |
| 15-Oct-18  |   2 |         12 | 1-2018-002233 |
| 20-Oct-18  |   1 |        100 | 1-2018-002233 |
+------------+-----+------------+---------------+

SELECT Qty,unit_price,LPO,
    case
    when issue_date <= '2018-03-31'  and issue_date >= '2018-01-01'  
    then (((qty) *(unit_price))  * 1.05 )      
    else    
    (((qty) *(unit_price))  * 1.05 )
    end   as Tot_inc_Tax
    from  My_Table 

---

根据你的逻辑，你可以试试这个

第一个使用

或

第二个使用

和

并确保一切都符合你的逻辑

SELECT Issue_date,Qty,unit_price,LPO,
    case
    when (issue_date BETWEEN '2018-01-01' AND '2018-06-30') OR unit_price IS NULL 
      THEN qty *LPO  * 1.05       
    when issue_date > '2018-03-31' AND unit_price IS NOT NULL 
      THEN qty * LPO  END 'Total_Inc_Tax'
from  My_Table 

---

一个计算选项是：

with my_table(Issue_date, qty, unit_price, LPO) as  
(
 select '2018-01-10',1,42 ,'1-2018-001166' union all
 select '2018-01-12',1,100,NULL            union all
 select '2018-09-20',1,25 ,NULL            union all
 select '2018-10-15',2,12 ,'1-2018-002233' union all
 select '2018-10-20',1,100,'1-2018-002233'     
)
select Qty,unit_price,LPO,
       (case
          when issue_date between '2018-01-01' and '2018-03-31'  
            then (((qty) *(unit_price))  * 1.05 )      
          when issue_date > '2018-03-31' then
          ( case when lpo is null then
                 (((qty) *(unit_price))  * 1.05 )
            else
                 (((qty) *(unit_price))) 
            end )
        end ) as Tot_inc_Tax
  from  My_Table;

您可以使用以下功能：

SELECT Qty,unit_price,LPO,
case
when issue_date between '2018-01-01' and '2018-03-31'  
then (((qty) *(unit_price))  * 1.05 )      
else   when  issue_date > '2018-03-31' and LPO is null
(((qty) *(unit_price))  * 1.05 )
end   as Tot_inc_Tax
from  My_Table 

---

需要将数量*LPO替换为数量*单价和（或LPO为空）

SELECT Qty,unit_price,LPO,
case
when issue_date between '2018-01-01' and '2018-03-31'  
then (((qty) *(unit_price))  * 1.05 )      
else   when  issue_date > '2018-03-31' and LPO is null
(((qty) *(unit_price))  * 1.05 )
end   as Tot_inc_Tax
from  My_Table