Виктор Егоров wrote > 2013/6/1 Shenli Zhu < > zhushenli@ > > > >> Hi, there are 2 columns, flag(boolean) and num(integer),in a table. >> Table is like >> | flag | num | >> |------+-----| >> | 1 | 2 | \ 5 >> | 1 | 3 | / >> | 0 | 1 | \ 7 >> | 0 | 6 | / >> | 1 | 4 | \ 9 >> | 1 | 5 | / >> | ... | ... | >> I want to sum up the raw with the same continuous flags. What you want to do is possible and you have been provided some resources to do so. However, with the table you have provided it is not possible to implement such a solution. Tables do not have "order" to them inherently. You must decide on a mechanism to distinguish between the "1"s in the first group and the "1"s in the second group and code your query to ORDER BY using that mechanism before assigning group identifiers and performing the group sub-total. This is not an optional requirement. If you query works without doing that you are simply lucky and at some point in the future it can possibly stop working which means that you query is broken/buggy. Since your example looks made-up you are on your own for the "mechanism" but if time can be used you can possibly get away with either an "serial" column or a "current timestamp" column to enforce the order. David J. -- View this message in context: http://postgresql.1045698.n5.nabble.com/Sum-raw-with-the-same-continuous-flags-tp5757658p5757671.html Sent from the PostgreSQL - general mailing list archive at Nabble.com. -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
