1.使用视图
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create or replace procedure row_to_col(tabname in varchar2, group_col in varchar2, column_col in varchar2, value_col in varchar2, Aggregate_func in varchar2 default 'max', colorder in varchar2 default null, roworder in varchar2 default null, when_value_null in varchar2 default null, viewname in varchar2 default 'v_tmp')Authid Current_Useras sqlstr varchar2(2000):='create or replace view '||viewname||' as select '||group_col||' '; c1 sys_refcursor; v1 varchar2(100);begin open c1 for 'select distinct '||column_col||' from '||tabname||case when colorder is not null then ' order by '||colorder end; loop fetch c1 into v1; exit when c1%notfound; sqlstr:=sqlstr||chr(10)||','||case when when_value_null is not null then 'nvl(' end|| Aggregate_func||'(decode(to_char('||column_col||'),'''||v1||''','||value_col||'))'|| case when when_value_null is not null then chr(44) ||when_value_null||chr(41) end||'"'||v1||'"'; end loop; close c1; sqlstr:=sqlstr||' from '||tabname||' group by '||group_col||case when roworder is not null then ' order by '||roworder end; execute immediate sqlstr;end row_to_col; |
这里修改了传入参数名，使其更容易理解。继续使用了创建视图这个方法，当然也可以改成用游标传出。
参数：
tabname 需要进行行转列操作的表名；
group_col 查询结果要按某列或某些列分组的字段名；
column_col 要从行转成列的字段；
value_col 需要聚合的值字段；
Aggregate_func 选用的聚合函数，可选，默认为max；
colorder 行转列后列的排序，可选；
roworder 行转列后记录的排序，可选；
when_value_null 若value_col字段的值聚合后为空，则转换成该值，可选；
viewname 创建的视图名称，可选，默认为v_tmp。
举例：
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--测试数据create table rowtocol_test asselect 2009 year,1 month,'部门1' dept,50000 expenditure from dualunion all select 2009,2,'部门1',20000 from dualunion all select 2009,2,'部门1',30000 from dualunion all select 2010,1,'部门1',35000 from dualunion all select 2009,2,'部门2',40000 from dualunion all select 2009,3,'部门2',25000 from dualunion all select 2010,2,'部门3',60000 from dualunion all select 2009,2,'部门3',15000 from dualunion all select 2009,2,'部门3',10000 from dual; |
我现在想根据year和month分组，将部门转成列。
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SQL> select * from rowtocol_test; YEAR MONTH DEPT EXPENDITURE---------- ---------- ----- ----------- 2009 1 部门1 50000 2009 2 部门1 20000 2009 2 部门1 30000 2010 1 部门1 35000 2009 2 部门2 40000 2009 3 部门2 25000 2010 2 部门3 60000 2009 2 部门3 15000 2009 2 部门3 10000 9 rows selected SQL> execute row_to_col('rowtocol_test','year,month','dept','expenditure');PL/SQL procedure successfully completed SQL> select * from v_tmp; YEAR MONTH 部门1 部门3 部门2---------- ---------- ---------- ---------- ---------- 2009 1 50000 2010 1 35000 2009 3 25000 2009 2 30000 15000 40000 2010 2 60000 SQL> |
这个结果可能不是我们想要的，重新调用过程，使用几个可选参数
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SQL> execute row_to_col('rowtocol_test','year,month','dept','expenditure',Aggregate_func => 'sum',colorder => 'dept',roworder => '1,2',when_value_null => '0'); PL/SQL procedure successfully completed SQL> select * from v_tmp; YEAR MONTH 部门1 部门2 部门3---------- ---------- ---------- ---------- ---------- 2009 1 50000 0 0 2009 2 50000 40000 25000 2009 3 0 25000 0 2010 1 35000 0 0 2010 2 0 0 60000 SQL> |
进行行转列的也可以是视图
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SQL> create view view_rowtocol as select * from rowtocol_test where year=2009; View created SQL> execute row_to_col('view_rowtocol','year,month','dept','expenditure',Aggregate_func => 'sum',colorder => 'dept',roworder => '1,2',when_value_null => '0'); PL/SQL procedure successfully completed SQL> select * from v_tmp; YEAR MONTH 部门1 部门2 部门3---------- ---------- ---------- ---------- ---------- 2009 1 50000 0 0 2009 2 50000 40000 25000 2009 3 0 25000 0 SQL> |
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2.稍加修改，使用函数，返回游标。或利用过程里的传出参数
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create or replace function row_to_col_func(tabname in varchar2, group_col in varchar2, column_col in varchar2, value_col in varchar2, Aggregate_func in varchar2 default 'max', colorder in varchar2 default null, roworder in varchar2 default null, when_value_null in varchar2 default null )return sys_refcursorAuthid Current_Useras sqlstr varchar2(2000):='select '||group_col||' '; c1 sys_refcursor; v1 varchar2(100); cur sys_refcursor;begin open c1 for 'select distinct '||column_col||' from '||tabname||case when colorder is not null then ' order by '||colorder end; loop fetch c1 into v1; exit when c1%notfound; sqlstr:=sqlstr||chr(10)||','||case when when_value_null is not null then 'nvl(' end|| Aggregate_func||'(decode(to_char('||column_col||'),'''||v1||''','||value_col||'))'|| case when when_value_null is not null then chr(44) ||when_value_null||chr(41) end||'"'||v1||'"'; end loop; close c1; open cur for sqlstr||' from '||tabname||' group by '||group_col||case when roworder is not null then ' order by '||roworder end; return cur;end row_to_col_func; |
在pl/sql dev中可以在sql窗口执行，查看结果
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select row_to_col_func('rowtocol_test','year,month','dept','expenditure',Aggregate_func => 'sum',colorder => 'dept',roworder => '1,2',when_value_null => '0')from dual;ROW_TO_COL_FUNC('ROWTOCOL_TEST<Cursor>YEAR MONTH 部门1 部门2 部门32009 1 50000 0 02009 2 50000 40000 250002009 3 0 25000 02010 1 35000 0 02010 2 0 0 60000 |