大约有 40,000 项符合查询结果(耗时:0.0327秒) [XML]
How to get these two divs side-by-side?
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I still think display: table-cell will get results closer to what he means (since then they will have the same height etcetera) but this way will certainly work.
– ehdv
Mar 22 '11 at 6:09
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Reshaping data.frame from wide to long format
I have some trouble to convert my data.frame from a wide table to a long table.
At the moment it looks like this:
9 Answe...
What is the difference between HAVING and WHERE in SQL?
..., CNT=Count(1)
From Address
Where State = 'MA'
Group By City
Gives you a table of all cities in MA and the number of addresses in each city.
This code:
select City, CNT=Count(1)
From Address
Where State = 'MA'
Group By City
Having Count(1)>5
Gives you a table of cities in MA with more than ...
Algorithm for creating a school timetable
...dering if there are known solutions for algorithm of creating a school timetable. Basically, it's about optimizing "hour-dispersion" (both in teachers and classes case) for given class-subject-teacher associations. We can assume that we have sets of classes, lesson subjects and teachers associated ...
Mechanisms for tracking DB schema changes [closed]
...mber of files numbered 1.sql, 2.sql, 3.sql, etc. The script uses one extra table to store the current version number of the database. The N.sql files are crafted by hand, to go from version (N-1) to version N of the database.
They can be used to add tables, add columns, migrate data from an old to ...
Extract a substring according to a pattern
...sapply(strsplit(string, ":"), "[", 2)
## [1] "E001" "E002" "E003"
3) read.table
read.table(text = string, sep = ":", as.is = TRUE)$V2
## [1] "E001" "E002" "E003"
4) substring
This assumes second portion always starts at 4th character (which is the case in the example in the question):
substring(st...
Retrieving the last record in each group - MySQL
There is a table messages that contains data as shown below:
27 Answers
27
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What is the proper way to re-attach detached objects in Hibernate?
...nate Session (a.k.a Persistence Context) and is not mapped to any database table row is considered to be in the New (Transient) state.
To become persisted we need to either explicitly call the EntityManager#persist method or make use of the transitive persistence mechanism.
Persistent (Managed)
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How many GCC optimization levels are there?
...is a strong indicator that there are only 3 levels.
opts.c:default_options_table
opt_levels is so interesting, that we grep OPT_LEVELS_3_PLUS, and come across opts.c:default_options_table:
static const struct default_options default_options_table[] = {
/* -O1 optimizations. */
{ OPT_LEVELS_...
How to make an empty div take space
...p;nbsp; to the empty items.
I don't understand why you're not using a <table> here, though? They will do this kind of stuff automatically.
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