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最新推荐文章于 2024-02-15 12:55:18 发布

原创最新推荐文章于 2024-02-15 12:55:18 发布 · 183 阅读

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本文提供了Oracle中将多行数据转换为一行的SQL示例，以及使用Java编译命令进行编译的方法。Oracle SQL示例展示了如何通过CASE WHEN语句结合窗口函数ROW_NUMBER实现多行转一行的操作。

1.Oracle多行转一行SQL示例:
WITH a AS
(SELECT 1 c1, 'a' c2, 1 c3 FROM dual
UNION ALL
SELECT 1 c1, 'b' c2, 2 c3 FROM dual
UNION ALL
SELECT 2 c1, 'c' c2, 1 c3 FROM dual
UNION ALL
SELECT 2 c1, 'd' c2, 3 c3 FROM dual)
SELECT
c1,
max(CASE WHEN rnum = 1 THEN c2 END ) c2_1,
max(CASE WHEN rnum = 2 THEN c2 END ) c2_2,
max(CASE WHEN rnum = 1 THEN c3 END ) c3_1,
max(CASE WHEN rnum = 2 THEN c3 END ) c3_2 FROM
(
SELECT a.*, row_number() OVER(PARTITION BY c1 ORDER BY c2) rnum FROM a
) a1
GROUP BY c1;
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2.java编译命令:
javac -cp servlet-api.jar; xxx.java
javac -cp servlet-api.jar; -target 1.6 -source 1.6 xxx.java