行列置换oracle

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?create table sale_list(month varchar(6),sell number(11,2));insert into sale_list values('201101',1000);insert into sale_list values('201102',2000);insert into sale_list values('201103',3000);insert into sale_list values('201104',4000);insert into sale_list values('201105',5000);insert into sale_list values('201106',6000); commit;

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DECODE(value, if1, then1, if2,then2, if3,then3, . . . else )

????? select

???? 　substrb(month,1,4),

???? 　sum(decode(substrb(month,5,2),'01',sell,0)) "1",　　　　sum(decode(substrb(month,5,2),'02',sell,0)) "2",　　　　sum(decode(substrb(month,5,2),'03',sell,0)) "3",　　　　sum(decode(substrb(month,5,2),'04',sell,0)) "4",　　　　sum(decode(substrb(month,5,2),'05',sell,0)) "5",　　　　sum(decode(substrb(month,5,2),'06',sell,0)) "6"　　　　from sale_list

　　　　group by substrb(month,1,4);