Sum raw with the same continuous flags - Mailing list pgsql-general

From Shenli Zhu
Subject Sum raw with the same continuous flags
Date
Msg-id CAA9w1xiLGDM9nuRr=_N8Roh46_fdrGDHy_huc=gi-S=bMquz2g@mail.gmail.com
Whole thread Raw
Responses Re: Sum raw with the same continuous flags  (Andreas Kretschmer <akretschmer@spamfence.net>)
Re: Sum raw with the same continuous flags  (Victor Yegorov <vyegorov@gmail.com>)
List pgsql-general
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. E.g. flag in 1st and
2nd row are both 1, 3rd and 4th are both 0, 5th and 6th are both 1. So
the table becomes
| flag | num |
|------+-----|
|    1 |   5 |
|    0 |   7 |
|    1 |   9 |

Can I do this in SQL or PL/pgSQL? Any suggestions are welcome.

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