DB2 Sql 用于在大型机中进行转置

Question

想要在大型机 Db2 Sql 中实现以下

Answer 1

在 Db2 for LUW 上，这将起作用。大型机SQL将类似。只需使用表名代替TABLE(VALUES ... AS(..)位

SELECT
MAX(CASE WHEN RN = 1 THEN Student_no END) AS Student_no_1
,    MAX(CASE WHEN RN = 1 THEN S_Name     END) AS S_Name_1    
,    MAX(CASE WHEN RN = 1 THEN Marks      END) AS Marks_1
,    MAX(CASE WHEN RN = 2 THEN Student_no END) AS Student_no_2
,    MAX(CASE WHEN RN = 2 THEN S_Name     END) AS S_Name_2
,    MAX(CASE WHEN RN = 2 THEN Marks      END) AS Marks_2
,    MAX(CASE WHEN RN = 3 THEN Student_no END) AS Student_no_3
,    MAX(CASE WHEN RN = 3 THEN S_Name     END) AS S_Name_3
,    MAX(CASE WHEN RN = 3 THEN Marks      END) AS Marks_3
FROM
(   SELECT ROW_NUMBER() OVER(ORDER BY Student_no) AS RN
,     Student_no
,     S_Name
,     Marks
FROM
TABLE(VALUES( 2, 'Abc', 89),( 5, 'dfg', 35),( 9, 'qwe', 56))
AS (Student_no, S_Name, Marks)
)
STUDENT_NO_1 S_NAME_1 MARKS_1 STUDENT_NO_2 S_NAME_2 MARKS_2 STUDENT_NO_3 S_NAME_3 MARKS_3
------------ -------- ------- ------------ -------- ------- ------------ -------- -------
2 Abc           89            5 dfg           35            9 qwe           56