Re: [SQL] about LEFT and INNER JOIN - Mailing list pgsql-sql
Sorry, I forgot specify the PostgreSQL version which is 9.4
Ing. Eliober Cleger Despaigne
Vicedecano de Extensión y Residencia, Facultad 3
Telf: 8040
De: Feike Steenbergen [mailto:feikesteenbergen@gmail.com]
Enviado el: martes, 30 de mayo de 2017 2:00
Para: Eliober Cleger Despaigne
CC: pgsql-sql@postgresql.org
Asunto: Re: [SQL] about LEFT and INNER JOIN
The join strategies PostgreSQL can use are outlined here:
https://www.postgresql.org/docs/current/static/planner-optimizer.html
basically either a:
- nested loop join O(n*m)
- merge join O(n+m)
- hash join O(n+m)
regards,
Feike
On 23 May 2017 at 20:38, Eliober Cleger Despaigne <ecleger@uci.cu> wrote:
Grettings
I need to know which algorithm uses the INNER JOIN and LEFT JOIN. If would be possible, I need to know their costs too in O(n) notation.
La @universidad_uci es Fidel. Los jóvenes no fallaremos. #HastaSiempreComandante #HastalaVictoriaSiempre
La @universidad_uci es Fidel. Los jóvenes no fallaremos. #HastaSiempreComandante #HastalaVictoriaSiempre