日期:2014-05-16 浏览次数:20611 次
listagg函数是在oracle11g中新引入的聚合函数,当然也可以作为分析函数来使用。该函数可以基于分组内特定列的排序,将测量列进行拼接合并。
示例:
在10g中,该函数不被支持
SQL> select prod_id, LISTAGG(cust_first_name||' '||cust_last_name,';') WITHIN GROUP (order by amount_sold) cust_name from sales, customers 2 where sales.cust_id = customers.cust_id and cust_gender = 'M' and cust_credit_limit = 15000 and prod_id between 15 and 18 and channel_id =2 and time_id > to_date('01-06-01','YY-MM-DD') group by prod_id; 3 4 5 select prod_id, LISTAGG(cust_first_name||' '||cust_last_name,';') WITHIN GROUP (order by amount_sold) cust_name from sales, customers * 第 1 行出现错误: ORA-00923: 未找到要求的 FROM 关键字在11g中,运行结果如下:
SQL> l 1 select prod_id, LISTAGG(cust_first_name||' '||cust_last_name,';') WITHIN GROUP (order by amount_sold) cust_name from sales, customers 2 where sales.cust_id = customers.cust_id and cust_gender = 'M' 3 and cust_credit_limit = 15000 and prod_id between 15 and 18 4 and channel_id =2 and time_id > to_date('01-06-01','YY-MM-DD') 5* group by prod_id SQL> / PROD_ID CUST_NAME ---------- ---------------------------------------------------------------- 15 Mason Murray;Helga Nickols;Roxanne Crocker;Glenn Wong;Roxanne Crocker;Franklin Hagan;Franklin Hagan; Ransom Wiser;Reyburn Markman 16 Forrest Lindsey;Helga Nickols;Helga Nickols;Roxanne Crocker;Garrett Manson;Roxanne Crocker;Franklin Hagan;Prane Oppy;Franklin Hagan;Bud Smyth;Reyburn Markman 17 Garrett Manson;Roxanne Crocker;Helga Nickols;Roxanne Crocker;Helga Nickols;Mason Murray;Ethan Jeffre ys;Franklin Hagan;Prane Oppy;Royd Ricketts 18 Erik Ready;Garrett Manson;Forrest Lindsey;Franklin Hagan;Franklin Hagan;Reyburn Markman
当然,listagg也可以基于over()的分区。
示例:
SQL> l 1 select time_id,prod_id,min(amount_sold),listagg(min(amount_sold),';') within group (order by prod_id) over (partition by time_id) cust_list 2 from sales where time_id > to_date('20-DEC-01','DD-MON-YY','NLS_DATE_LANGUAGE = American') and prod_id between 120 and 125 3* group by prod_id,time_id SQL> / TIME_ID PROD_ID MIN(AMOUNT_SOLD) CUST_LIST ------------------- ---------- ---------------- ---------------------------------- 2001-12-21 00:00:00 120 51.36 51.36;10.81 2001-12-21 00:00:00 121 10.81 51.36;10.81 2001-12-22 00:00:00 120 51.36 51.36;10.81;20.23;56.12;17.79;15.67 2001-12-22 00:00:00 121 10.81 51.36;10.81;20.23;56.12;17.79;15.67 2001-12-22 00:00:00 122 20.23 51.36;10.81;20.23;56.12;17.79;15.67 2001-12-22 00:00:00 123 56.12 51.36;10.81;20.23;56.12;17.79;15.67 2001-12-22 00:00:00 124 17.79 51.36;10.81;20.23;56.12;17.79;15.67 2001-12-22 00:00:00 125 15.67 51.36;10.81;20.23;56.12;17.79;15.67 2001-12-23 00:00:00 120 51.36 51.36;10.49;20.23;57.86;17.79;15.67 2001-12-23 00:00:00 121 10.49 51.36;10.49;20.23;57.86;17.79;15.67 2001-12-23 00:00:00 122 20.23 51.36;10.49;20.23;57.86;17.79;15.67 TIME_ID PROD_ID MIN(AMOUNT_SOLD) CUST_LIST ------------------- ---------- ---------------- ---------------------------------- 2001-12-23 00:00:00 123 57.86 51.36;10.49;20.23;57.86;17.79;15.67 2001-12-23 00:00:00 124 17.79 51.36;10.49;20.23;57.86;17.79;15.67 2001-12-23 00:00:00 125 15.67 51.36;10.49;20.23;57.86;17.79;15.67 2001-12-24 00:00:00 120 51.36 51.36;10.49;20.23;56.12;17.79;15.67 2001-12-24 00:00:00 121 10.49 51.36;10.49;20.23;56.12;17.79;15.67 2001-12-24 00:00:00 122 20.23 51.36;10.49;20.23;56.12;17.79;