[英]SQL Pivot on varchar columns
我有一个看起来像这样的结果集:
FlightCode col2 Col3 SourceAirportCode
Flight007 NYC SOURCE 64
Flight008 ORD TARGET 87
Flight007 SEA TARGET NULL
Flight008 PHX SOURCE NULL
我试图达到的最终结果是:
FlightCode Source Target SourceAirportCode
Flight007 NYC SEA 64
Fight008 PHX ORD 87
这是 pivot 问题吗? 我尝试了一些旋转但没有运气,或者我只是对 Pivot 了解不够。这是
使用架构和插入语句。 请指教。
假设航班代码实际匹配,则使用条件聚合:
select flightcode,
max(case when col3 = 'SOURCE' then col2 end) as source,
max(case when col3 = 'TARGET' then col2 end) as target,
max(SourceAirportCode) as SourceAirportCode
from t
group by flightcode;
您可以使用自联接并将一个表视为源,将另一个表视为目标。
WITH flight(FlightCode, col2, Col3, SourceAirportCode)
AS
(
SELECT 'Flight007','NYC','SOURCE',64 UNION
SELECT 'Flight008','ORD','TARGET',87 UNION
SELECT 'Flight007','SEA','TARGET',NULL UNION
SELECT 'Flight008','PHX','SOURCE',NULL
)
SELECT f.FlightCode, s.col2 as 'SOURCE', t.col2 as 'TARGET',
f.SourceAirportCode
FROM flight f
JOIN flight s ON s.Col3 = 'SOURCE' AND s.FlightCode = f.FlightCode
JOIN flight t ON t.Col3 = 'TARGET' AND t.FlightCode = f.FlightCode
WHERE f.SourceAirportCode IS NOT NULL
FlightCode SOURCE TARGET SourceAirportCode
Flight007 NYC SEA 64
Flight008 PHX ORD 87
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