Re: Importing data from CSV into a table with array and composite types
2018-05-20 7:36 GMT+02:00 a <372660...@qq.com>:
> Thank you so much. BTW, may I ask one more question that, how should I
> select every first element of the array??
>
> I know that "select p[:] from f" will print all element of the p array,
> but I probably would want to present result as "select p[:].a from f", but
> the statement does not work.
>
> May I as the correct statement of displaying all first element of the
> composite type in an array??
>
it is not easy - for example, that I sent you can write a query
postgres=# select array_agg(a) from f, unnest(pv) where f.c = 1000;
┌───┐
│ array_agg │
╞═══╡
│ {10,30} │
└───┘
(1 row)
> Thank you!
>
> Shore
>
>
> -- Original message --
> *From:* "Pavel Stehule";
> *Sendtime:* Friday, May 18, 2018 5:46 PM
> *To:* "a"<372660...@qq.com>;
> *Cc:* "pgsql-general";
> *Subject:* Re: Importing data from CSV into a table with array and
> composite types
>
> Hi
>
> 2018-05-18 10:37 GMT+02:00 a <372660...@qq.com>:
>
>> Hi:
>>
>> I would like to import data from a csv table. But the table that is going
>> to be inserted is constructed with arrays and composite types, also with
>> array of composite.
>>
>> I have tried many ways of inserting but fail. Can anyone help? Thank you
>> so much.
>>
>
> create type p as (a int, b int);
> create table f(pv p[], c int);
> insert into f values(array[(10,20),(30,40)]::p[], 1000);
> insert into f values(array[(1,20),(3,40)]::p[], -1000);
>
> postgres=# copy f to stdout csv;
> "{""(10,20)"",""(30,40)""}",1000
> "{""(1,20)"",""(3,40)""}",-1000
> Time: 0,391 ms
>
> So you have to respect this format. CSV doesn't know a arrays, doesn't
> know composite - so these values are passed as string
>
> Regards
>
> Pavel
>
Re: Importing data from CSV into a table with array and composite types
Thank you so much. BTW, may I ask one more question that, how should I select
every first element of the array??
I know that "select p[:] from f" will print all element of the p array, but I
probably would want to present result as "select p[:].a from f", but the
statement does not work.
May I as the correct statement of displaying all first element of the composite
type in an array??
Thank you!
Shore
-- Original message --
From: "Pavel Stehule";
Sendtime: Friday, May 18, 2018 5:46 PM
To: "a"<372660...@qq.com>;
Cc: "pgsql-general";
Subject: Re: Importing data from CSV into a table with array and composite types
Hi
2018-05-18 10:37 GMT+02:00 a <372660...@qq.com>:
Hi:
I would like to import data from a csv table. But the table that is going to be
inserted is constructed with arrays and composite types, also with array of
composite.
I have tried many ways of inserting but fail. Can anyone help? Thank you so
much.
create type p as (a int, b int);
create table f(pv p[], c int);
insert into f values(array[(10,20),(30,40)]::p[], 1000);
insert into f values(array[(1,20),(3,40)]::p[], -1000);
postgres=# copy f to stdout csv;
"{""(10,20)"",""(30,40)""}",1000
"{""(1,20)"",""(3,40)""}",-1000
Time: 0,391 ms
So you have to respect this format. CSV doesn't know a arrays, doesn't know
composite - so these values are passed as string
Regards
Pavel
Importing data from CSV into a table with array and composite types
Hi: I would like to import data from a csv table. But the table that is going to be inserted is constructed with arrays and composite types, also with array of composite. I have tried many ways of inserting but fail. Can anyone help? Thank you so much.
