Re: [PERFORM] INSERT question

От: george young
Тема: Re: [PERFORM] INSERT question
Дата: ,
Msg-id: 20041229135858.71f8c3cf.gry@ll.mit.edu
(см: обсуждение, исходный текст)
Ответ на: INSERT question  (sarlav kumar)
Список: pgsql-novice

Скрыть дерево обсуждения

INSERT question  (sarlav kumar, )
 Re: INSERT question  (Bruno Wolff III, )
 Re: INSERT question  (Tom Lane, )
  Re: INSERT question  (sarlav kumar, )
 Re: [PERFORM] INSERT question  (george young, )

On Mon, 13 Dec 2004 08:28:39 -0800 (PST)
sarlav kumar <> threw this fish to the penguins:

> Hi All,
>
> I have a question regarding multiple inserts.
> The following function inserts for each country found in country table, values into merchant_buyer_country.
>
>
-----------------------------------------------------------------------------------------------------------------------------------------
>         CSQLStatement st( sql );
>         CSQLStatement st1( sql );
>         SQLINTEGER rows;
>         long num_codes = 0;
>         rows = st.Select( "SELECT * FROM merchant_buyer_country where merchant_id = %lu ",merchant_id );
>         if  ( rows )
>                 return 0;
>     char code[4];
>         rows = st.Select( "SELECT code FROM country WHERE send IS NOT NULL OR receive IS NOT NULL" );
>     SQLBindCol( st.hstmt, 1, SQL_C_CHAR, code, sizeof(code), 0 );
>    long i;
>    for (i = 0; i < rows; i++ )
>    {
>           st.Fetch();
>           st1.Command("INSERT INTO merchant_buyer_country (merchant_id,country,enabled,group_id)  VALUES(%lu ,'%s',
true,%lu )", merchant_id, 
>  code,group_id);
>    }
>         st.CloseCursor();
>     st1.CloseCursor();
>         return 1;
>
-----------------------------------------------------------------------------------------------------------------------------------------
>
> On looking at the log file, I saw separate inserts being performed, and each insert takes about 1 second.
>
> insert into merchant_buyer_country (merchant_id,country,enabled,group_id) values(1203,'IN','true',1);
> insert into merchant_buyer_country merchant_id,country,enabled,group_id)  values(1203,'US','true',1);
> insert into merchant_buyer_country merchant_id,country,enabled,group_id) values (1203,'AR','true',1);
> insert into merchant_buyer_country (merchant_id,country,enabled,group_id) values(1203,'AZ','true',1);
> insert into merchant_buyer_country merchant_id,country,enabled,group_id) values (1203,'BG','true',1);
> insert into merchant_buyer_country merchant_id,country,enabled,group_id) values(1203,'SP','true',1);
> .....
>
>
>
>
>
>
> There are more than 100 countries and this takes a lot of time for the inserts to complete.
> Is there a way to write the INSERT as follows?
>
> INSERT into merchant_buyer_country (merchant_id,country,enabled,group_id)  values (1203,
> (SELECT code FROM country WHERE send IS NOT NULL OR receive IS NOT NULL), 'true',1);
>
> I tried this, but I get the following problem:
> ERROR:  More than one tuple returned by a subselect used as an expression.
>
> I know there is a way to this, but I am not sure where I am going wrong. Can someone please help me figure this out.

Try:

insert into merchant_buyer_country select 1203,code,true,1 from country where send is not null or receive is not null;

-- George Young
--
"Are the gods not just?"  "Oh no, child.
What would become of us if they were?" (CSL)


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