PostgreSQL Oracle 相容性之 - insert all into ... 多表寫入

摘要： 標籤 PostgreSQL , Oracle , 多表批量寫入 , insert all into , CTE 背景 Oracle支援 insert all 的語法，同時往多個表插入。 https://docs.oracle.com/cd/B19306_01/se...

標籤

PostgreSQL , Oracle , 多表批量寫入 , insert all into , CTE

背景

Oracle支援 insert all 的語法，同時往多個表插入。

ofollow,noindex" target="_blank">https://docs.oracle.com/cd/B19306_01/server.102/b14200/statements_9014.htm

https://docs.oracle.com/cd/B19306_01/server.102/b14200/statements_9014.htm#i2125362

PostgreSQL可以通過CTE語法達到同樣的效果。

https://www.postgresql.org/docs/11/static/queries-with.html

Oracle insert all into 例子

create table a(id int, c1 int, c2 int);

create table b(id int, c1 int, c2 int);


set autotrace on;

insert all
into a (id,c1) values (id, col1)
into b (id,c2) values (id, col2)
select rownum as id, trunc(dbms_random.value(0, 100)) as col1, trunc(dbms_random.value(0, 100)) as col2 from dual connect by level <=10000;

20000 rows created.

Execution Plan
----------------------------------------------------------
Plan hash value: 702343910

-----------------------------------------------------------------------------------------
| Id| Operation| Name | Rows| Bytes | Cost (%CPU)| Time|
-----------------------------------------------------------------------------------------
|0 | INSERT STATEMENT||1 |39 |2(0)| 00:00:01 |
|1 |MULTI-TABLE INSERT||||||
|2 |INTO| A|||||
|3 |INTO| B|||||
|4 |VIEW||1 |39 |2(0)| 00:00:01 |
|5 |COUNT||||||
|*6 |CONNECT BY WITHOUT FILTERING||||||
|7 |FAST DUAL||1 ||2(0)| 00:00:01 |
-----------------------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

6 - filter(LEVEL<=10000)


Statistics
----------------------------------------------------------
531recursive calls
661db block gets
205consistent gets
0physical reads
392344redo size
823bytes sent via SQL*Net to client
932bytes received via SQL*Net from client
3SQL*Net roundtrips to/from client
6sorts (memory)
0sorts (disk)
20000rows processed

PostgreSQL CTE例子

create table a(id int, c1 int, c2 int);

create table b(id int, c1 int, c2 int);

insert all
into a (id,c1) values (id, col1)
into b (id,c2) values (id, col2)
select id, random() col1, random() col2 from generate_series(1,10000) t(id);

ERROR:42601: syntax error at or near "all"
LINE 1: insert all
^
LOCATION:scanner_yyerror, scan.l:1087

with tmp as (select id, random() col1, random() col2 from generate_series(1,10000) t(id)),
ins1 as (insert into a (id,c1) select id,col1 from tmp)
insert into b (id,c2) select id,col2 from tmp;

INSERT 0 10000

postgres=# select count(*) from a;
 count
-------
 10000
(1 row)

postgres=# select count(*) from b;
 count
-------
 10000
(1 row)


postgres=# select * from a limit 10;
 id | c1 | c2
----+----+----
1 |0 |
2 |1 |
3 |1 |
4 |0 |
5 |1 |
6 |0 |
7 |1 |
8 |0 |
9 |0 |
 10 |0 |
(10 rows)

postgres=# select * from b limit 10;
 id | c1 | c2
----+----+----
1 ||0
2 ||0
3 ||1
4 ||1
5 ||0
6 ||1
7 ||1
8 ||1
9 ||0
 10 ||0
(10 rows)