Oracle 行转列总结 Case When,Decode,PIVOT 三种方式

Decode 方式

SELECT a.COUNTRY AS "国家",

SUM(DECODE(a.SEX, 1, a.POPULCATION)) AS "男",

SUM(DECODE(a.SEX, 2, a.POPULCATION)) AS "女"

FROM populations a

GROUP BY a.COUNTRY

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Case When 方式

SELECT a.COUNTRY AS "国家",

SUM(CASE

WHEN a.SEX = 1 THEN

a.POPULCATION

END) AS "男",

SUM(CASE

WHEN a.SEX = 2 THEN

a.POPULCATION

END) AS "女"

FROM populations a

GROUP BY a.COUNTRY

--------------------------------------

PIVOT 方式 11G特有的方式

SELECT *

FROM (SELECT a.COUNTRY AS "国家", a.SEX, a.POPULCATION FROM populations a)

PIVOT(

SUM(POPULCATION)

FOR SEX IN(1 AS "男",2 AS "女"))
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