如何在sql中将两行合并为一行？

Question

我有一张桌子

EmployeeID    IndividualPay  FamilyPay   IsActive
    1            200          300        true
    1            100          150        false

但我希望输出如下(我想使用此输出与其他表的内连接)

EmployeeID  IndPay_IsActive  IndPay_IsNotActive FamilyPay_IsActive   FamilyPay_IsNotActive 
    1            200                 100              300                   150

我已经调查过PIVOT,但不知道如何在我的情况下使用它.

Answer 1

这种类型的转换称为枢轴.您没有指定正在使用的数据库,但您可以CASE在任何系统中使用带有表达式的聚合函数:

select employeeid,
  max(case when IsActive = 'true' then IndividualPay end) IndPay_IsActive,
  max(case when IsActive = 'false' then IndividualPay end) IndPay_IsNotActive,
  max(case when IsActive = 'true' then FamilyPay end) FamilyPay_IsActive,
  max(case when IsActive = 'false' then FamilyPay end) FamilyPay_IsNotActive
from yourtable
group by employeeid

请参阅SQL Fiddle with Demo

根据您的数据库,如果您同时访问PIVOT和UNPIVOT函数,则可以使用它们来获取结果.该UNPIVOT函数将IndividualPay和FamilyPay列转换为行.完成后,您可以使用以下PIVOT函数创建四个新列:

select *
from
(
  select employeeid,
    case when isactive = 'true'
      then col+'_IsActive'
      else col+'_IsNotActive' end col, 
    value
  from yourtable
  unpivot
  (
    value
    for col in (IndividualPay, FamilyPay)
  ) unpiv
) src
pivot
(
  max(value)
  for col in (IndividualPay_IsActive, IndividualPay_IsNotActive,
              FamilyPay_IsActive, FamilyPay_IsNotActive)
) piv

请参阅SQL Fiddle with Demo.

两者都给出相同的结果:

| EMPLOYEEID | INDIVIDUALPAY_ISACTIVE | INDIVIDUALPAY_ISNOTACTIVE | FAMILYPAY_ISACTIVE | FAMILYPAY_ISNOTACTIVE |
----------------------------------------------------------------------------------------------------------------
|          1 |                    200 |                       100 |                300 |                   150 |