[original] Oracle implements generate_series of PGSQL
PostgreSQL has a function to generate sequences, which makes it easy to create data. Here I use ORACLE to implement the generate_series function of PGSQL.
POSTGRESQL.
T_girl=# select * from generate_series (1cm10) Generate_series- 1 2 3 4 5 6 7 8 9 10 (10 lines) time: 1.290 mst_girl=# select * from generate_series Generate_series- 1 3 5 7 9 (5 lines) time: 0.431 mst_girl=# select * from generate_series Generate_series- 1 4 7 10 (4 lines) time: 0.879 mst_girl=# select * from generate_series Generate_series- 2 58 (3 lines record) time: 0.867 mst_girl=# select count (*) from generate_series (1 mine1000) Count- 1000 (1 line record) time: 1.142 mst_girl=# select to_char (now () -'1 day'::interval * n as result from generate_series (1m 10) g (n) Result- 2015-12-08 2015-12-07 2015-12-06 2015-12-05 2015-12-04 2015-12-03 2015-12-02 2015-12-01 2015-11-30 2015-11-29 (10 lines) time: 17.284 ms
ORACLE:
12:10:34 SQL > select * from table (ytt_generate_series (1penny 10)) COLUMN_VALUE-1 2 3 4 5 6 7 8 9 10 10 10 rows have been selected. Elapsed time: 00: 00: 00.0212 SQL 10 SQL > select * time (ytt_generate_series (1mem10 Magi 2)) COLUMN_VALUE-1 3 5 7 9 elapsed time: 00: 00: 00.0012 SQL 10 SQL > select * time (ytt_generate_series (1mem10 Magazine 3)) COLUMN_VALUE-1 4 7 10 Elapsed time: 00: 00: 00.0012 SQL 10 SQL > select * from table (ytt_generate_series (2Jing 10 Magi 3)) COLUMN_VALUE-2 5 8 elapsed time: 00: 00: 00.0212 SQL 11 SQL > select count (*) from table (ytt_generate_series (1pm 1000)) COUNT (*)-1000 Elapsed time: 00: 00: 00.1313 SQL 32 SQL > select to_char (sysdate-n 'YYYY-MM-DD') from table (ytt_generate_series (1m 10)) TO_CHAR (SY-2015-12-082015-12-072015-12-062015-12-052015-12-042015-12-032015-12-022015-12-012015-11-302015-11-29 10 rows have been selected. Time spent: 00: 00: 00.01
Attach the code:
-- Declare result set.create or replace type ytt_num is object (n number); / create or replace type numbers_table is table of ytt_num;/-- Function body.-- Created by ytt.-- 2015/12/9create or replace function ytt_generate_series (f_start_num number: = 1,-- Start number.f_end_num number,-- Finish number.f_step_num number: = 1-- Step.) return numbers_table pipelinedis list numbers_table: = numbers_table (); I number: = 0 J number: = 1 Increase nested table's size begin I: = frankstartnumb; j: = 1;-- List.extend (f_end_num);-- Loop begin. While i
