[SQL] SELECT with WHERE clause by column number
Hi! I need to make a query like this: SELECT id FROM myTable WHERE column-number = 'value'; (PS: The id column is the primary key of myTable). That is a select using column number in the WHERE clause what don't exists in SQL. I need this because there's a situation in my program where I don't have the column name. I've solved that querying Postgresql the name of the column with that number, and then creating the SELECT query. But this solution is slow... two database calls... Can I do this with a single query or in a faster way through SQL, an internal function or through a Procedural Language? Thanks Carlos Henrique Iazzetti Santos Compels Informática Santa Rita do Sapucaí - MG BRAZIL www.compels.net ___ Você quer respostas para suas perguntas? Ou você sabe muito e quer compartilhar seu conhecimento? Experimente o Yahoo! Respostas ! http://br.answers.yahoo.com/
Res: [SQL] SELECT with WHERE clause by column number
All my columns have the same data type: text. So it's much easier. Carlos Henrique Iazzetti Santos Compels Informática Santa Rita do Sapucaí - MG www.compels.net - Mensagem original De: Richard Huxton Para: Carlos Santos <[EMAIL PROTECTED]> Cc: Lista PostgreSQL SQL Enviadas: Segunda-feira, 18 de Dezembro de 2006 15:25:27 Assunto: Re: [SQL] SELECT with WHERE clause by column number Carlos Santos wrote: > SELECT id FROM myTable WHERE column-number = 'value'; > (PS: The id column is the primary key of myTable). > > That is a select using column number in the WHERE clause what don't exists in > SQL. > > I need this because there's a situation in my program where I don't have the > column name. > I've solved that querying Postgresql the name of the column with that number, > and then creating the SELECT query. > But this solution is slow... two database calls... If you don't know what the column is, how do you know what you are testing against? Or what type it is, for that matter? Anyway, just have build a list of column-name,column-type pairs for relevant tables at application start-up, or store it in a configuration file. Unless you're building/changing tables all the time, that should work. I'm curious as to what type of application can usefuly query a database without knowing what structure it has. -- Richard Huxton Archonet Ltd ---(end of broadcast)--- TIP 4: Have you searched our list archives? http://archives.postgresql.org ___ Yahoo! Acesso Grátis - Internet rápida e grátis. Instale o discador agora! http://br.acesso.yahoo.com
[SQL] Query a select that returns all the fields of an specific value of primary key without knownig the name of the single column's primary key?
Hi! I need to query a select that returns all the fields of an specific primary key, but I don't have the single column's name that is constrained as primary key. How can I do that? Something like: SELECT * FROM myTable WHERE myTable.pkey = 'foo'; Thanks Carlos Henrique Iazzetti Santos Compels Informática Santa Rita do Sapucaí - MG www.compels.net ___ O Yahoo! está de cara nova. Venha conferir! http://br.yahoo.com
[SQL] LOCK command inside a TRANSACTION
Hi! I need Postgresql somehow does this for me: - if an user query a select on a table, the rows of the table in the result of this select can not be updated or deleted by another user until this one update, delete or discard the changes on those rows. I've found something about the LOCK command inside a TRANSACTION but I didn't see how I could do that yet. Does anybody have any ideas? Carlos Henrique Iazzetti Santos Compels Informática Santa Rita do Sapucaí - MG Brazil www.compels.net __ Fale com seus amigos de graça com o novo Yahoo! Messenger http://br.messenger.yahoo.com/
[SQL] How can I know if a row is Locked?
How can I know if a row is locked by another transaction. I have in a transaction like that: BEGIN; SELECT * FROM compels.teste WHERE id = '1' FOR UPDATE; PS1: where id is the primary key. PS2: The COMMIT command is done after a long time. In this case the row with the primary-key equals to '1' will be locked to other transactions until the COMMIT command be executed. So, how can I detect if this row is locked? Tks Carlos Henrique Iazzetti Santos Compels Informática Santa Rita do Sapucaí - MG www.compels.net __ Fale com seus amigos de graça com o novo Yahoo! Messenger http://br.messenger.yahoo.com/
