资源一:来源 Jason_zhu的博客 http://jason-zhu.iteye.com/blog/430647 以一张薪资表为例,表结构如下: 表结构中,每个员工id对应有多个薪资项目以及金额,需要查询时转向,将每个员工的薪资项目转为横向一行显示。 在直接查询(加入一些限制条件以缩小结
资源一:来源 Jason_zhu的博客 http://jason-zhu.iteye.com/blog/430647
以一张薪资表为例,表结构如下:
表结构中,每个员工id对应有多个薪资项目以及金额,需要查询时转向,将每个员工的薪资项目转为横向一行显示。
在直接查询(加入一些限制条件以缩小结果集),
Sql代码
SELECT ssp_pay_empid, ssp_pay_sdate, ssp_pay_edate, ssp_pay_type, ssp_pay_amount, ssp_pay_item FROM ssp_pay where ssp_pay_empid = 00000073 and ssp_pay_type = 'RT' and ssp_pay_item IN ('/101','/103','/401','/402') and ssp_pay_sdate = '2007-08-01'
得到如下结果:
需要将上述查询结果显示为一行,则使用SQL Server 2005新增的PIVOT,通过将表达式某一列中的唯一值转换为输出中的多个列来旋转表值表达式,并在必要时对最终输出中所需的任何其余列值执行聚合。
执行如下SQL:
Sql代码
select ssp_pay_empid, ssp_pay_sdate, ssp_pay_edate, ssp_pay_type, [/101], [/103], [/401], [/402] from ( SELECT ssp_pay_empid, ssp_pay_sdate, ssp_pay_edate, ssp_pay_type, ssp_pay_amount, ssp_pay_item FROM ssp_pay where ssp_pay_empid = 00000073 and ssp_pay_type = 'RT' and ssp_pay_sdate = '2007-08-01' ) AS SourceTable PIVOT (SUM(ssp_pay_amount) FOR ssp_pay_item IN ([/101],[/103],[/401],[/402])) AS PivotTable
结果为:
资源二 来源 http://www.cnblogs.com/gkl0818/archive/2009/02/25/1398078.html
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
这一类型的转换可以借助于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;
select distinct c1 ,get_c2(c1) cc2 from table;
或者不用pl/sql,利用分析函数和 CONNECT_BY 实现:
SELECT c1, SUBSTR (MAX (SYS_CONNECT_BY_PATH (c2, ';')), 2) NAME
FROM (SELECT c1, c2, rn, LEAD (rn) OVER (PARTITION BY c1 ORDER BY rn) rn1
FROM (SELECT c1, c2, ROW_NUMBER () OVER (ORDER BY c2) rn
FROM t))
START WITH rn1 IS NULL
CONNECT BY rn1 = PRIOR rn
GROUP BY c1;
3、列数不固定(交叉表行列转置)
这种是比较麻烦的一种,需要借助pl/sql:
原始数据:
CLASS1 CALLDATE CALLCOUNT
1 2005-08-08 40
1 2005-08-07 6
2 2005-08-08 77
3 2005-08-09 33
3 2005-08-08 9
3 2005-08-07 21
转置后:
CALLDATE CallCount1 CallCount2 CallCount3
------------ ---------- ---------- ----------
2005-08-09 0 0 33
2005-08-08 40 77 9
2005-08-07 6 0 21
试验如下:
1). 建立测试表和数据
CREATE TABLE t(
class1 VARCHAR2(2 BYTE),
calldate DATE,
callcount INTEGER
);
INSERT INTO t(class1, calldate, callcount)
VALUES ('1', TO_DATE ('08/08/2005', 'MM/DD/YYYY'), 40);
INSERT INTO t(class1, calldate, callcount)
VALUES ('1', TO_DATE ('08/07/2005', 'MM/DD/YYYY'), 6);
INSERT INTO t(class1, calldate, callcount)
VALUES ('2', TO_DATE ('08/08/2005', 'MM/DD/YYYY'), 77);
INSERT INTO t(class1, calldate, callcount)
VALUES ('3', TO_DATE ('08/09/2005', 'MM/DD/YYYY'), 33);
INSERT INTO t(class1, calldate, callcount)
VALUES ('3', TO_DATE ('08/08/2005', 'MM/DD/YYYY'), 9);
INSERT INTO t(class1, calldate, callcount)
VALUES ('3', TO_DATE ('08/07/2005', 'MM/DD/YYYY'), 21);
COMMIT ;
2). 建立ref cursor准备输出结果集
CREATE OR REPLACE PACKAGE pkg_getrecord
IS
TYPE myrctype IS REF CURSOR;
END pkg_getrecord;
/
3). 建立动态sql交叉表函数,输出结果集
CREATE OR REPLACE FUNCTION fn_rs
RETURN pkg_getrecord.myrctype
IS
s VARCHAR2 (4000);
CURSOR c1 IS
SELECT ',sum(case when Class1='
|| class1
|| ' then CallCount else 0 end)'
|| ' "CallCount'
|| class1
|| '"' c2
FROM t
GROUP BY class1;
r1 c1%ROWTYPE;
list_cursor pkg_getrecord.myrctype;
BEGIN
s := 'select CallDate ';
OPEN c1;
LOOP
FETCH c1 INTO r1;
EXIT WHEN c1%NOTFOUND;
s := s || r1.c2;
END LOOP;
CLOSE c1;
s := s || ' from T group by CallDate order by CallDate desc ';
OPEN list_cursor FOR s;
RETURN list_cursor;
END fn_rs;
/
4). 测试在sql plus下执行:
var results refcursor;
exec :results := fn_rs;
print results;
CALLDATE CallCount1 CallCount2 CallCount3
--------------- ---------- ---------- ----------
2005-08-09 0 0 33
2005-08-08 40 77 9
2005-08-07 6 0 21