選擇記錄作爲配對父母子女

Question

記錄被保存爲與pairkey列鏈接的同一個表中的父母子女，然後甚至父母被分成與scndleg列鏈接的兩條腿。也就是說，將有兩條父母腿與scndleg列相鏈接，並且每個父母將在pairkey列中具有父母的seqnno父母的子女。

看這個fiddle

，我需要選擇一個完整的批次爲

Both legs of interlinked parents 
UNION 
All children of these two parents 

，然後其他批次以下相同的模式等在fiddle

Answer 1

編輯新所示查詢版本（鏈接到SQLFiddle末尾）：

SELECT 
    seqnno, 
    narration, 
    pairkey, 
    scndleg 
    FROM (
    SELECT p.*, LEAST(seqnno, scndleg) related_leg_min_id 
     FROM pairs p 
) 
START WITH scndleg IS NOT NULL 
CONNECT BY pairkey = PRIOR seqnno AND scndleg IS NULL 
ORDER BY connect_by_root(related_leg_min_id), scndleg DESC NULLS LAST, pairkey 
; 

輸出：

 SEQNNO NARRATION     PAIRKEY SCNDLEG 
---------- ------------------------ ---------- ---------- 
     1 1st leg parent     1   4 
     4 2nd leg parent     4   1 
     2 1st leg child      1    
     3 1st leg child      1    
     5 2nd leg child      4    
     6 2nd leg child      4    
     7 another 1st leg parent   7   10 
     10 another 2nd leg parent   10   7 
     8 another 1st leg child    7    
     9 another 1st leg child    7    
     11 another 2nd leg child   10    
     12 another 2nd leg child   10  

SQLFiddle