Re: Difference in query plan when using = or > in where clause - Mailing list pgsql-performance

Radhika S wrote:
> I am curious as to why this occurs. Why does an = change the query plan so
> drastically?
>
> When my query is:
> Select count(*) from View_A WHERE tradedate = '20070801';
> The query plan is as below:
> ...
> But when my query is:
> Select count(*) from View_A WHERE tradedate BETWEEN '20070801' and
> '20070901';
> The query plan is:
> ...

In short, the planner estimates that "tradedate BETWEEN '20070801' and
'20070901'" matches more rows than "tradatedate = '20070801'"

--
  Heikki Linnakangas
  EnterpriseDB   http://www.enterprisedb.com