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PostgreSQL - max number of parameters in “IN” clause?
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explain select * from test where id in (values (1), (2));
QUERY PLAN
Seq Scan on test (cost=0.00..1.38 rows=2 width=208)
Filter: (id = ANY ('{1,2}'::bigint[]))
But if try 2nd query:
explain select * from test where id = an...
LIMIT 10..20 in SQL Server
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For SQL Server 2012 + you can use.
SELECT *
FROM sys.databases
ORDER BY name
OFFSET 5 ROWS
FETCH NEXT 5 ROWS ONLY
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How to log a method's execution time exactly in milliseconds?
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const uint64_t elapsedMTU = endTime - startTime;
// Get information for converting from MTU to nanoseconds
mach_timebase_info_data_t info;
if (mach_timebase_info(&info))
handleErrorConditionIfYoureBeingCareful();
// Get elapsed time in nanoseconds:
const double elapsedNS = (double)elapsed...
Ruby Arrays: select(), collect(), and map()
...re, to check the :qty key, you'd do something like the following:
details.select{ |item| item[:qty] != "" }
That will give you all items where the :qty key isn't an empty string.
official select documentation
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I have 2 dates in PHP, how can I run a foreach loop to go through all of those days?
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Converting to unix timestamps makes doing date math easier in php:
$startTime = strtotime( '2010-05-01 12:00' );
$endTime = strtotime( '2010-05-10 12:00' );
// Loop between timestamps, 24 hours at a time
for ( $i = $startTi...
How do you get a string from a MemoryStream?
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Using a StreamReader to convert the MemoryStream to a String.
<Extension()> _
Public Function ReadAll(ByVal memStream As MemoryStream) As String
' Reset the stream otherwise you will just get an empty string.
' Remember the position s...
How to get a list of user accounts using the command line in MySQL?
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Use this query:
SELECT User FROM mysql.user;
Which will output a table like this:
+-------+
| User |
+-------+
| root |
+-------+
| user2 |
+-------+
As Matthew Scharley points out in the comments on this answer, you can group by the ...
Extract a dplyr tbl column as a vector
...2 3.62 3.54 4.11
A nice way to do this in v0.2 of dplyr:
iris2 %>% select(Species) %>% collect %>% .[[5]]
Or if you prefer:
iris2 %>% select(Species) %>% collect %>% .[["Species"]]
Or if your table isn't too big, simply...
iris2 %>% collect %>% .[["Species"]]
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How to paste over without overwriting register
Does anyone know of a way to paste over a visually selected area without having the selection placed in the default register?
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How do we count rows using older versions of Hibernate (~2009)?
...eturn int and use this form:
int count = ((Long)getSession().createQuery("select count(*) from Book").uniqueResult()).intValue();
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