2、不定列行列转换 如 c1 c2 -------------- 1 我 1 是 1 谁 2 知 2 道 3 不 …… 转换为 1 我是谁 2 知道 3 不 这一类型的转换必须借助于PL/SQL来完成,这里给一个例子 CREATE OR REPLACE FUNCTION get_c2(tmp_c1 NUMBER) RETURN VARCHAR2 IS Col_c2 VARCHAR2(4000); BEGIN FOR cur IN (SELECT c2 FROM t WHERE c1=tmp_c1) LOOP Col_c2 := Col_c2||cur.c2; END LOOP; Col_c2 := rtrim(Col_c2,1); RETURN Col_c2; END; / SQL> select distinct c1 ,get_c2(c1) cc2 from table;即可
select id,sum(decode(sex,"1",1,0)) "1",sum(decode(sex,"2",1,0)) "2" from table_name group by id;
二楼的能不能动态一点呀,如果我sex 的标识为3 或5呢?
若字段数不确定,需要通过存储过程来拼 --创建过程 create or replace procedure proc as sqlstr varchar2(2000):='create or replace view v_tmp as select "UNION"'; begin for cur1 in (select distinct sex from tab1) loop sqlstr:=sqlstr||' ,count(decode(sex,'||cur1.sex||',1))"'||cur1.sex||'"'; end loop; sqlstr:=sqlstr||' from tab1 group by "UNION"'; execute immediate sqlstr; end; --调用 begin proc; end; --查看结果 select * from v_tmp
WITH A AS (SELECT '004' 部门, '2' 性别 FROM DUAL UNION ALL SELECT '002' 部门, '2' 性别 FROM DUAL UNION ALL SELECT '002' 部门, '2' 性别 FROM DUAL UNION ALL SELECT '003' 部门, '1' 性别 FROM DUAL UNION ALL SELECT '002' 部门, '1' 性别 FROM DUAL) SELECT 部门, COUNT(DECODE(性别, '1',1)), COUNT(DECODE(性别, '2', 1)) FROM A GROUP BY 部门 ORDER BY 部门;
count(decode(sex,2,1))"2"
from tab1
group by union
[A]1、固定列数的行列转换
如
student subject grade
---------------------------
student1 语文 80
student1 数学 70
student1 英语 60
student2 语文 90
student2 数学 80
student2 英语 100
……
转换为
语文 数学 英语
student1 80 70 60
student2 90 80 100
……
语句如下:
select student,sum(decode(subject,'语文', grade,null)) "语文",
sum(decode(subject,'数学', grade,null)) "数学",
sum(decode(subject,'英语', grade,null)) "英语"
from table
group by student
2、不定列行列转换
如
c1 c2
--------------
1 我
1 是
1 谁
2 知
2 道
3 不
……
转换为
1 我是谁
2 知道
3 不
这一类型的转换必须借助于PL/SQL来完成,这里给一个例子
CREATE OR REPLACE FUNCTION get_c2(tmp_c1 NUMBER)
RETURN VARCHAR2
IS
Col_c2 VARCHAR2(4000);
BEGIN
FOR cur IN (SELECT c2 FROM t WHERE c1=tmp_c1) LOOP
Col_c2 := Col_c2||cur.c2;
END LOOP;
Col_c2 := rtrim(Col_c2,1);
RETURN Col_c2;
END;
/
SQL> select distinct c1 ,get_c2(c1) cc2 from table;即可
--创建过程
create or replace procedure proc
as
sqlstr varchar2(2000):='create or replace view v_tmp as select "UNION"';
begin
for cur1 in (select distinct sex from tab1)
loop
sqlstr:=sqlstr||'
,count(decode(sex,'||cur1.sex||',1))"'||cur1.sex||'"';
end loop;
sqlstr:=sqlstr||' from tab1 group by "UNION"';
execute immediate sqlstr;
end;
--调用
begin
proc;
end;
--查看结果
select * from v_tmp
这个procedure没有out参数,怎么接受结果集呀。 是不是要加个结果集的out 参数呀。
直接在过程里建视图,然后查询视图会更方便
这个过程产生的视图固定为v_tmp
运行完过程后查询v_tmp视图即可
(SELECT '004' 部门, '2' 性别
FROM DUAL
UNION ALL
SELECT '002' 部门, '2' 性别
FROM DUAL
UNION ALL
SELECT '002' 部门, '2' 性别
FROM DUAL
UNION ALL
SELECT '003' 部门, '1' 性别
FROM DUAL
UNION ALL
SELECT '002' 部门, '1' 性别 FROM DUAL)
SELECT 部门, COUNT(DECODE(性别, '1',1)), COUNT(DECODE(性别, '2', 1)) FROM A
GROUP BY 部门 ORDER BY 部门;