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Mysql: Select rows from a table that are not in another
How to select all rows in one table that do not appear on another?
8 Answers
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Get selected option from select element
I am trying to get the selected option from a dropdown and populate another item with that text, as follows. IE is barking up a storm and it doesn't work in Firefox:
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UITextView style is being reset after setting text property
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Sitting with this for hours, I found the bug.
If the property "Selectable" = NO it will reset the font and fontcolor when setText is used.
So turn Selectable ON and the bug is gone.
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Ruby on Rails form_for select field with class
I am beating my head against the wall on this one. I want to make a simple select tag using the f.select tag but nothing I do works. I put an example below:
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How to select rows that have current day's timestamp?
I am trying to select only today's records from a database table.
9 Answers
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Which is fastest? SELECT SQL_CALC_FOUND_ROWS FROM `table`, or SELECT COUNT(*)
...irm this - I just updated a query with 4 joins on a 168,000 row database. Selecting just the first 100 rows with a SQL_CALC_FOUND_ROWS took over 20 seconds; using a separate COUNT(*) query took under 5 seconds (for both count + results queries).
– Sam Dufel
Ju...
Fast way to discover the row count of a table in PostgreSQL
...in your case.
Instead of getting the exact count (slow with big tables):
SELECT count(*) AS exact_count FROM myschema.mytable;
You get a close estimate like this (extremely fast):
SELECT reltuples::bigint AS estimate FROM pg_class where relname='mytable';
How close the estimate is depends on ...
Rails: select unique values from a column
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Model.select(:rating)
Result of this is a collection of Model objects. Not plain ratings. And from uniq's point of view, they are completely different. You can use this:
Model.select(:rating).map(&:rating).uniq
or this (mo...
How to select between brackets (or quotes or …) in Vim?
...Computed solution coefficients:
As CMS noted, this works for visual mode selection as well - just use vi), vi}, vi', etc.
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Is there a way to access the “previous row” value in a SELECT statement?
...d to order by some column for this to be meaningful. Something like this:
select t1.value - t2.value from table t1, table t2
where t1.primaryKey = t2.primaryKey - 1
If you know how to order things but not how to get the previous value given the current one (EG, you want to order alphabetically) ...