基于参数的select语句中的条件列答案

【问题标题】：Conditional columns in select statement based on parameters基于参数的select语句中的条件列
【发布时间】：2020-04-06 12:22:33
【问题描述】：

我有以下条件：

- If ouk_shipment.shipper_parent_id = Parameter1 OR
ouk_shipment.shipper_id = Parameter2
=====> ouk_shipment.first_mwb_ref_id
- If ouk_shipment.cnee_parent_id = Parameter1 OR
ouk_shipment.cnee_id = Parameter2
=====> ouk_shipment.last_mwb_ref_id

**Parameter1和Parameter2：我们在SQL运行时输入。

我在这里尝试实现以下目标：

Select case when condition 1=True then ouk_shipment.first_mwb_ref_id
            when condition 2=True then ouk_shipment.last_mwb_ref_id End AS Col1
From ouk_shipment

如何在我的 SQL 中添加条件？请检查

【问题讨论】：

标签： sql oracle select parameters conditional-statements

【解决方案1】：

你可以这样做 - 注意我做了 'XXX' 假设它是 varchar，你可以将它更改为 Integer for Int

SELECT CASE WHEN  ouk_shipment.shipper_parent_id = COALESCE(Parameter1,'XXX') 
                      OR ouk_shipment.shipper_id = COALESCE(Parameter2,'YYYY')
              THEN ouk_shipment.first_mwb_ref_id
            WHEN ouk_shipment.shipper_parent_id = COALESCE(Parameter1,'XXX') 
                OR ouk_shipment.shipper_id = COALESCE(Parameter2,'YYYY')
              THEN ouk_shipment.last_mwb_ref_id End AS Col1
FROM ouk_shipment

【讨论】：

恐怕 CASE 语法错误。

【解决方案2】：

你99%都在那里

select 
  case 
    when ouk_shipment.shipper_parent_id = Parameter1 OR ouk_shipment.shipper_id = Parameter2 then ouk_shipment.first_mwb_ref_id
    when ouk_shipment.cnee_parent_id = Parameter1 OR ouk_shipment.cnee_id = Parameter2 then ouk_shipment.last_mwb_ref_id
  end col  
from  ouk_shipment
...

【讨论】：