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I like the presentation of the guide. I wish something like this had been available when I started. The "Filtering Data" example at the very bottom of this pa
by brobinson 11y ago
I like the presentation of the guide. I wish something like this had been available when I started.
The "Filtering Data" example at the very bottom of this page [1] could be improved a bit. It's using >= AND <= for finding records between certain dates when BETWEEN is generally better for this. Since the guide is aimed at "beginners and experienced users", maybe a different example could be used or the BETWEEN version could be added below it as an example of cases where there's a more efficient way to filter data?
[1] http://www.postgresguide.com/sql/select.html#filtering-data http://www.postgresguide.com/sql/select.html#filtering-data
- joevandyk 11y agoYou gotta be careful when using BETWEEN. BETWEEN does a >= x AND a <= y Usually, you want a >= x AND a < y http://www.postgresql.org/docs/9.3/static/functions-comparison.html http://www.postgresql.org/docs/9.3/static/functions-comparis...
- brobinson 11y agoGood point! Edit: my parent post is wrong, the guide is using <, not <=, but I can't edit it now.
- vincentdm 11y agoI recently replaced all my a >= x AND a < y with BETWEEN, and then I realised I got burned by what you describe :-) It's been on the Trello to-do to fix it for weeks...
- pilif 11y agoThis is why I love the Postgres range types so much (http://www.postgresql.org/docs/9.4/static/rangetypes.html http://www.postgresql.org/docs/9.4/static/rangetypes.html). With those, you get to chose based on the value whether your ranges include the boundaries or not. Even better: you get to chose for both start and end.