Question

我在Impala上使用SQL

我正在查询的表格看起来像

客户名称shop1 shop1number shop2 shop2number shop3 shop3number

TOM AB 111 AA 231 AC 321

AMY AC 121 AB 213 AD 231

Franck AD 123 AE 233 AB 234

enter image description here 在这里，数字是客户忠诚度数字，挑战是如果我正在寻找商店1（AB）的忠诚度数字，我不知道当客户填写他们的忠诚度数字时它属于哪一列，这是他们的选择按照他们描述的任何顺序输入数字

Answer 1

如果我理解正确，您正在寻找与商店相关的所有忠诚度数字，因此一种方法是首先使用union all将行数据添加到列中，然后搜索商店;让我们说AB。

select * from
(
select customername, shop1 as shop, shop1number as shopnumber
from table1
union all
select customername, shop2 as shop, shop2number as shopnumber
from table1
union all
select customername, shop3 as shop, shop3number as shopnumber
from table1
    ) t
where t.shop = 'AB';

<强>结果：

+--------------+------+------------+
| customername | shop | shopnumber |
+--------------+------+------------+
| AMY          | AB   |        213 |
| TOM          | AB   |        111 |
| Franck       | AB   |        234 |
+--------------+------+------------+

<强> DEMO

Answer 2

declare @shop varchar(10)
set @shop='AB'
select cname, 
case when  shop1=@shop then shop1 
when shop2=@shop then shop2
when shop3=@shop then shop3
end
as shop, 
shop1number as shopnumber
from tblcus

当前一列使用SQL满足某些条件时，如何选择下一列

2 个答案: