标签：col tin rgb 运用 查询 data- nbsp exp 思考
感谢出题者，如有冒犯，请与我联系，希望和大家一起学习交流。(目前使用oracle数据库环境编写sql)
题目
有如下ABC三列和几组数据
想得到如下结果
该如何写查询？
读者可以试着自己思考写下，再往下翻... 如有不同解题方式，欢迎大家一起交流。
1.运用聚合函数和dense_rank
sys@WIL> with t AS 2 (SELECT ‘aaa‘ A,‘1‘ B,‘X‘ C 3 FROM dual 4 UNION ALL 5 SELECT ‘aaa‘ A,‘2‘ B,‘Y‘ C 6 FROM dual 7 UNION ALL 8 SELECT ‘bbb‘ B,‘3‘ B,‘X‘ C 9 FROM dual 10 UNION ALL 11 SELECT ‘bbb‘ B,‘4‘ B,‘X‘ C 12 FROM dual 13 UNION ALL 14 SELECT ‘ccc‘ A,‘5‘ B,‘Y‘ C 15 FROM dual 16 UNION ALL 17 SELECT ‘ccc‘ A,‘6‘ B,‘Y‘ C 18 FROM dual ) 19 SELECT DISTINCT A, 20 BB, 21 case 22 WHEN max(RN) over(partition by A)>1 THEN 23 ‘1‘ 24 ELSE C 25 END CC 26 FROM 27 (SELECT A, 28 sum(B) over(partition by A) BB, 29 C, 30 dense_rank() over(partition by A 31 ORDER BY C) RN 32 FROM t); A BB C --- ---------- - aaa 3 1 bbb 7 X ccc 11 Y
2.运用lag函数：
sys@ESWIFT> with t AS 2 (SELECT ‘aaa‘ A,‘1‘ B,‘X‘ C 3 FROM dual 4 UNION ALL 5 SELECT ‘aaa‘ A,‘2‘ B,‘Y‘ C 6 FROM dual 7 UNION ALL 8 SELECT ‘bbb‘ B,‘3‘ B,‘X‘ C 9 FROM dual 10 UNION ALL 11 SELECT ‘bbb‘ B,‘4‘ B,‘X‘ C 12 FROM dual 13 UNION ALL 14 SELECT ‘ccc‘ A,‘5‘ B,‘Y‘ C 15 FROM dual 16 UNION ALL 17 SELECT ‘ccc‘ A,‘6‘ B,‘Y‘ C 18 FROM dual ) 19 SELECT A, 20 BB, 21 CC 22 FROM 23 (SELECT A, 24 sum(B) over(partition by A) BB, 25 row_number()over(partition by A 26 ORDER BY A,B) rn,case 27 WHEN c=lag(C) over(partition by A 28 ORDER BY A,B) THEN 29 C 30 ELSE ‘1‘ 31 END CC 32 FROM t) 33 WHERE rn=2 ; A BB C --- ---------- - aaa 3 1 bbb 7 X ccc 11 Y
标签：col tin rgb 运用 查询 data- nbsp exp 思考
原文地址：https://www.cnblogs.com/willspring/p/12891997.html
