将列选择为行以进行导出

Question

我有一个名为'transactions'的数据库表,有多个列.对于每个事务行,我需要从指定列表生成每列一行的导出

交易表

ID, DoNotEmail, DoNotMail, DoNotPhone, DoNotSMS
1000, true,    false,      true,       true

以下规则需要适用.

设置DoNotEmail然后输出'DNE'

设置DoNotMail然后输出'DNM'

设置DoNotPhone然后输出'DNP'

设置DoNotSMS然后输出'DNS'

出口需要看起来像:

ID, Suppressions
1000,  DNE
1000,  DNP
1000,  DNS

我真的很困惑,我能让它工作的唯一方法是将每个列的insert语句分成两个临时表非常可怕.Urgh.

这可能吗？

谢谢你的帮助.

达伦

抱歉格式化.

Answer 1

如果您只有四列,这可能会有效:

SELECT id, 
       'DNE' AS Suppressions 
FROM   transactions 
WHERE  donotemail = 'true' 
UNION ALL 
SELECT id, 
       'DNM' AS Suppressions 
FROM   transactions 
WHERE  donotmail = 'true' 
UNION ALL 
SELECT id, 
       'DNP' AS Suppressions 
FROM   transactions 
WHERE  donotphone = 'true' 
UNION ALL 
SELECT id, 
       'DNS' AS Suppressions 
FROM   transactions 
WHERE  donotsms = 'true' 

SQL小提琴演示

Answer 2

另一种可以编写的方法是:

SELECT id,
  case col 
    when 'DoNotEmail' then 'DNE'
    when 'DoNotMail' then 'DNM'
    when 'DoNotPhone' then 'DNP'
    when 'DoNotSMS' then 'DNS'
  end Suppressions
FROM 
(
  SELECT t.ID,
    s.col,
    CASE s.col
      WHEN 'DoNotEmail' THEN DoNotEmail
      WHEN 'DoNotMail' THEN DoNotMail
      WHEN 'DoNotPhone' THEN DoNotPhone
      WHEN 'DoNotSMS' THEN DoNotSMS
    END AS DATA
  FROM Transactions t
  CROSS JOIN 
  (
    SELECT 'DoNotEmail' AS col
    UNION ALL SELECT 'DoNotMail'
    UNION ALL SELECT 'DoNotPhone'
    UNION ALL SELECT 'DoNotSMS'
  ) s
) s
where data = 'true';

请参阅SQL Fiddle with Demo.

由于您使用的是SQL Server,因此可以实现以下UNPIVOT功能:

select id,
  case col 
    when 'DoNotEmail' then 'DNE'
    when 'DoNotMail' then 'DNM'
    when 'DoNotPhone' then 'DNP'
    when 'DoNotSMS' then 'DNS'
  end Suppressions
from Transactions
unpivot
(
  value 
  for col in ([DoNotEmail], [DoNotMail], [DoNotPhone], [DoNotSMS])
) piv
where value = 'true'

请参阅SQL Fiddle with Demo