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MySQL - force not to use cache for testing speed of query
...ACHE (MySQL 5.7) option in your query.
(MySQL 5.6 users click HERE )
eg.
SELECT SQL_NO_CACHE * FROM TABLE
This will stop MySQL caching the results, however be aware that other OS and disk caches may also impact performance. These are harder to get around.
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How do I delete a fixed number of rows with sorting in PostgreSQL?
...
You could try using the ctid:
DELETE FROM logtable
WHERE ctid IN (
SELECT ctid
FROM logtable
ORDER BY timestamp
LIMIT 10
)
The ctid is:
The physical location of the row version within its table. Note that although the ctid can be used to locate the row version very quickly,...
How do I set the time zone of MySQL?
...+00:00'
@@global.time_zone variable
To see what value they are set to:
SELECT @@global.time_zone;
To set a value for it use either one:
SET GLOBAL time_zone = '+8:00';
SET GLOBAL time_zone = 'Europe/Helsinki';
SET @@global.time_zone = '+00:00';
(Using named timezones like 'Europe/Helsinki' ...
Selectively revert or checkout changes to a file in Git?
... @Jan Do other version control systems' revert command allow you to select which changes within a file are reverted? Genuinely asking, as I only have experience with CVS and Git. In Git, git checkout -- path/to/file is a single command that reverts all changes in that file, but this is not th...
sql query to return differences between two tables
...colum C, here are the records, which are present in table A but not in B:
SELECT A.*
FROM A
LEFT JOIN B ON (A.C = B.C)
WHERE B.C IS NULL
To get all the differences with a single query, a full join must be used, like this:
SELECT A.*, B.*
FROM A
FULL JOIN B ON (A.C = B.C)
WHERE A.C IS NUL...
How to do an update + join in PostgreSQL?
... coming from mysql it's unintuitive that the same join used for select won't also update just by adding a set phrase :( still - the syntax for this is probably easier for a newcomer to sql to master.
– WEBjuju
Jul 16 at 19:47
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How do I query for all dates greater than a certain date in SQL Server?
...
select *
from dbo.March2010 A
where A.Date >= Convert(datetime, '2010-04-01' )
In your query, 2010-4-01 is treated as a mathematical expression, so in essence it read
select *
from dbo.March2010 A
where A.Date &g...
How can I get column names from a table in Oracle?
...
You can query the USER_TAB_COLUMNS table for table column metadata.
SELECT table_name, column_name, data_type, data_length
FROM USER_TAB_COLUMNS
WHERE table_name = 'MYTABLE'
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Is there a way to make ellipsize=“marquee” always scroll?
... was generally very ordinary — except for the fact that it was marked as selected.
One line of code later and I had it working :)
textView.setSelected(true);
This makes sense, given what the Javadoc says:
A view can be selected or not. Note that selection is not the same as focus. Views ar...
“CASE” statement within “WHERE” clause in SQL Server 2008
...
Try the following:
select * From emp_master
where emp_last_name=
case emp_first_name
when 'test' then 'test'
when 'Mr name' then 'name'
end
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