[SQL] conditional aggregates
Hi list, Can anyone advise me on creating an aggregate that would take additional parameter as a condition ? For example, say I have a table like this id;value 1;45 2;13 3;0 4;90 I'd like to do something like this SELECT min_some_cond_aggregate(value,0) FROM table to get the minimal value from table greater than 0, in this case 13. I can't do SELECT min(value) FROM table WHERE value 0 as this will mess my other computations. My current solution involves a function operating on the output of array_accum from the docs, but I'm looking for more elegant solution. Is this possible at all ? I'm running 8.1. regards mk
Re: [SQL] conditional aggregates
Hello use a CASE statement http://www.postgresql.org/docs/7.4/static/functions-conditional.html Regards Pavel Stehule 2010/12/8 Marcin Krawczyk jankes...@gmail.com: Hi list, Can anyone advise me on creating an aggregate that would take additional parameter as a condition ? For example, say I have a table like this id;value 1;45 2;13 3;0 4;90 I'd like to do something like this SELECT min_some_cond_aggregate(value,0) FROM table to get the minimal value from table greater than 0, in this case 13. I can't do SELECT min(value) FROM table WHERE value 0 as this will mess my other computations. My current solution involves a function operating on the output of array_accum from the docs, but I'm looking for more elegant solution. Is this possible at all ? I'm running 8.1. regards mk -- 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] conditional aggregates
Yeah I know but I'm having problems creating sfunc fuction for the aggregate. regards mk 2010/12/8 Pavel Stehule pavel.steh...@gmail.com Hello use a CASE statement http://www.postgresql.org/docs/7.4/static/functions-conditional.html Regards Pavel Stehule 2010/12/8 Marcin Krawczyk jankes...@gmail.com: Hi list, Can anyone advise me on creating an aggregate that would take additional parameter as a condition ? For example, say I have a table like this id;value 1;45 2;13 3;0 4;90 I'd like to do something like this SELECT min_some_cond_aggregate(value,0) FROM table to get the minimal value from table greater than 0, in this case 13. I can't do SELECT min(value) FROM table WHERE value 0 as this will mess my other computations. My current solution involves a function operating on the output of array_accum from the docs, but I'm looking for more elegant solution. Is this possible at all ? I'm running 8.1. regards mk
Re: [SQL] conditional aggregates
something like ? Select min (case when X 0 then X end) HTH, Marc Mamin From: pgsql-sql-ow...@postgresql.org [mailto:pgsql-sql-ow...@postgresql.org] On Behalf Of Marcin Krawczyk Sent: Mittwoch, 8. Dezember 2010 14:20 To: Pavel Stehule Cc: pgsql-sql@postgresql.org Subject: Re: [SQL] conditional aggregates Yeah I know but I'm having problems creating sfunc fuction for the aggregate. regards mk 2010/12/8 Pavel Stehule pavel.steh...@gmail.com Hello use a CASE statement http://www.postgresql.org/docs/7.4/static/functions-conditional.html Regards Pavel Stehule 2010/12/8 Marcin Krawczyk jankes...@gmail.com: Hi list, Can anyone advise me on creating an aggregate that would take additional parameter as a condition ? For example, say I have a table like this id;value 1;45 2;13 3;0 4;90 I'd like to do something like this SELECT min_some_cond_aggregate(value,0) FROM table to get the minimal value from table greater than 0, in this case 13. I can't do SELECT min(value) FROM table WHERE value 0 as this will mess my other computations. My current solution involves a function operating on the output of array_accum from the docs, but I'm looking for more elegant solution. Is this possible at all ? I'm running 8.1. regards mk
Re: [SQL] conditional aggregates
Thanks, it working. pozdrowienia mk 2010/12/8 Marc Mamin m.ma...@intershop.de something like ? Select min (case when X 0 then X end) HTH, Marc Mamin *From:* pgsql-sql-ow...@postgresql.org [mailto: pgsql-sql-ow...@postgresql.org] *On Behalf Of *Marcin Krawczyk *Sent:* Mittwoch, 8. Dezember 2010 14:20 *To:* Pavel Stehule *Cc:* pgsql-sql@postgresql.org *Subject:* Re: [SQL] conditional aggregates Yeah I know but I'm having problems creating sfunc fuction for the aggregate. regards mk 2010/12/8 Pavel Stehule pavel.steh...@gmail.com Hello use a CASE statement http://www.postgresql.org/docs/7.4/static/functions-conditional.html Regards Pavel Stehule 2010/12/8 Marcin Krawczyk jankes...@gmail.com: Hi list, Can anyone advise me on creating an aggregate that would take additional parameter as a condition ? For example, say I have a table like this id;value 1;45 2;13 3;0 4;90 I'd like to do something like this SELECT min_some_cond_aggregate(value,0) FROM table to get the minimal value from table greater than 0, in this case 13. I can't do SELECT min(value) FROM table WHERE value 0 as this will mess my other computations. My current solution involves a function operating on the output of array_accum from the docs, but I'm looking for more elegant solution. Is this possible at all ? I'm running 8.1. regards mk
