Single Table Report With Calculated Column
От | Rich Shepard |
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Тема | Single Table Report With Calculated Column |
Дата | |
Msg-id | alpine.LNX.2.11.1408290609300.9118@localhost обсуждение исходный текст |
Ответы |
Re: Single Table Report With Calculated Column
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Список | pgsql-general |
I've read some on table partitioning and using nested select statements with group by, but have not found the syntax to produce the needed results. From a table I extract row counts grouped by three columns: select stream, sampdate, func_feed_grp, count(*) from benthos group by stream, sampdate, func_feed_grp order by stream, sampdate, func_feed_group; And I want to include the proportion of each count based on the total rows for each stream and sampdate. The totals are obtained with this statement: select stream, sampdate, count(*) as tot_cnt from benthos group by stream, sampdate order by stream, sampdate; What I do not know how to do is combine the two so the resulting table contains the columns stream, sampdate, count, proportion. I want to learn how to build the sub-select to get this result. Joe Celko's 'SQL for Smarties, 4th Ed.' has a close example in the chapter on table partitioning, but I could not apply that model to my table. TIA, Rich
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