| From: | Surafel Temesgen <surafel3000(at)gmail(dot)com> |
|---|---|
| To: | PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | FETCH FIRST clause PERCENT option |
| Date: | 2018-08-16 14:27:45 |
| Message-ID: | CALAY4q9Esidbuz4fvUrGA-uOHNwbEsntLZQ8p=_okDvaTzJ3pA@mail.gmail.com |
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| Lists: | pgsql-hackers |
FETCH FIRST with PERCENT option is SQL standard that state limit count to
be specified in a percentage in addition to specify it in exact count and
listed as one of Major features simply not implemented yet in recent wiki
page [1].
I implemented it by executing the query plan twice. One without limit
filter to find the total number of row that will be feed to limit node so
the exact limit count can be calculated and the query plan execute again
with limit filter with newly calculated exact count .
[1].https://wiki.postgresql.org/wiki/PostgreSQL_vs_SQL_Standard
Regards
Surafel
| Attachment | Content-Type | Size |
|---|---|---|
| fetch-wth-percent-v1.patch | text/x-patch | 23.2 KB |
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