Обсуждение: I'm in a fix... please help quick
Please quick help, because I'm in a fix 1 Tables: mounted device, the elements included in the devices, the link elements with devices (including the number of elements in the device), installation steps. 2 The counting of the number of elements needed to perform the contract assembly of a certain number of devices (eg, 100 units of computers in the configuration 1). -- View this message in context: http://postgresql.1045698.n5.nabble.com/I-m-in-a-fix-please-help-quick-tp5796044.html Sent from the PostgreSQL - pgadmin support mailing list archive at Nabble.com.
2014-03-14 18:09 GMT+09:00 liliwow <emka1994@gmail.com>: > Please quick help, because I'm in a fix > > 1 Tables: mounted device, the elements included in the devices, the link > elements with devices (including the number of elements in the device), > installation steps. > 2 The counting of the number of elements needed to perform the contract > assembly of a certain number of devices (eg, 100 units of computers in the > configuration 1). If this is some kind of database-related college assignment, you really should be asking on a more general list like pgsql-novices, not a support list for a particular tool. And you should explain what you are trying to find out and what steps you have taken so far to solve the problem. Regards Ian Barwick
On 2014-03-14, 2:09 AM, liliwow wrote: > Please quick help, because I'm in a fix > > 1 Tables: mounted device, the elements included in the devices, the link > elements with devices (including the number of elements in the device), > installation steps. > 2 The counting of the number of elements needed to perform the contract > assembly of a certain number of devices (eg, 100 units of computers in the > configuration 1). Generally speaking, generic assembly-of-parts queries, eg how many X do I need to make a Y, this tends to be recursive and so you probably want to use a WITH RECURSIVE somewhere in your query; such as that is what lets you do this query without having to write procedural code or a query that only works for a specific number of levels. -- Darren Duncan