Re: [SQL] using ordinal_position
> -Original Message- > From: John Fabiani [mailto:jo...@jfcomputer.com] > Sent: Thursday, June 07, 2012 7:18 PM > To: pgsql-sql@postgresql.org > Subject: using ordinal_position > > I'm attempting to retrieve data using a select statement without > knowing the column names. I know the ordinal position but not the name > of the column (happens to be a date::text and I have 13 fields). > > Below provides the name of the column in position 3: > > select column_name from (select column_name::text, ordinal_position > from information_schema.columns where > table_name='wk_test') as foo where ordinal_position = 3; > > But how can I use the above as a column name in a normal select > statement. > > Unlike other databases I just can't use ordinal position in the select > statement - RIGHT??? > > Johnf David gave you already pretty complete answer. I just wonder what are these "other" RDBMSs that allow to use ordinal column positions in a query? I am familiar with a few (in addition to Postgress), and none of them does that, not in "select" list., though everybody allow ordinal position from "select" list in "order by" and "group by". Regards, Igor Neyman -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
Re: [SQL] using ordinal_position
On 06/11/2012 06:53 AM, Igor Neyman wrote: -Original Message- From: John Fabiani [mailto:jo...@jfcomputer.com] Sent: Thursday, June 07, 2012 7:18 PM To: pgsql-sql@postgresql.org Subject: using ordinal_position I'm attempting to retrieve data using a select statement without knowing the column names. I know the ordinal position but not the name of the column (happens to be a date::text and I have 13 fields). Below provides the name of the column in position 3: select column_name from (select column_name::text, ordinal_position from information_schema.columns where table_name='wk_test') as foo where ordinal_position = 3; But how can I use the above as a column name in a normal select statement. Unlike other databases I just can't use ordinal position in the select statement - RIGHT??? Johnf David gave you already pretty complete answer. I just wonder what are these "other" RDBMSs that allow to use ordinal column positions in a query? I am familiar with a few (in addition to Postgress), and none of them does that, not in "select" list., though everybody allow ordinal position from "select" list in "order by" and "group by". Regards, Igor Neyman VFP uses position (you might not consider DBF a database). MsSQl (ordinal_position). Those are the only two I'm aware of. Johnf -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
Re: [SQL] using ordinal_position
> -Original Message- > From: John Fabiani [mailto:jo...@jfcomputer.com] > Sent: Monday, June 11, 2012 11:11 AM > To: Igor Neyman > Cc: pgsql-sql@postgresql.org > Subject: Re: using ordinal_position > > On 06/11/2012 06:53 AM, Igor Neyman wrote: > > > >> -Original Message- > >> From: John Fabiani [mailto:jo...@jfcomputer.com] > >> Sent: Thursday, June 07, 2012 7:18 PM > >> To: pgsql-sql@postgresql.org > >> Subject: using ordinal_position > >> > >> I'm attempting to retrieve data using a select statement without > >> knowing the column names. I know the ordinal position but not the > >> name of the column (happens to be a date::text and I have 13 > fields). > >> > >> Below provides the name of the column in position 3: > >> > >> select column_name from (select column_name::text, ordinal_position > >> from information_schema.columns where > >> table_name='wk_test') as foo where ordinal_position = 3; > >> > >> But how can I use the above as a column name in a normal select > >> statement. > >> > >> Unlike other databases I just can't use ordinal position in the > >> select statement - RIGHT??? > >> > >> Johnf > > David gave you already pretty complete answer. > > I just wonder what are these "other" RDBMSs that allow to use ordinal > column positions in a query? > > I am familiar with a few (in addition to Postgress), and none of them > does that, not in "select" list., though everybody allow ordinal > position from "select" list in "order by" and "group by". > > > > Regards, > > Igor Neyman > > > > > > > VFP uses position (you might not consider DBF a database). MsSQl > (ordinal_position). Those are the only two I'm aware of. > > Johnf Did you mean MySQL or MS SQL? Because MS SQL Server does not allow ordinal position AFAIK. Igor -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
