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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 ...
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 ...
UITableViewCell with UITextView height in iOS 7?
How can I calculate the height of an UITableViewCell with an UITextView in it in iOS 7?
12 Answers
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Pretty-print an entire Pandas Series / DataFrame
...te_yearfirst, encoding, and many many more: pandas.pydata.org/pandas-docs/stable/options.html
– nealmcb
Jan 19 '17 at 14:15
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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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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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count(*) vs count(column-name) - which is more correct? [duplicate]
...hich values of column is not NULL, whereas COUNT(*) counts all rows of the table.
– PureSilence
Oct 3 '19 at 7:49
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In where shall I use isset() and !empty()
...nd the answer is:
$var = "";
var_dump(isset($var));
The type comparison tables in PHP’s manual is quite handy for such questions.
isset basically checks if a variable has any value other than null since non-existing variables have always the value null. empty is kind of the counter part to iss...
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...
How do I write LINQ's .Skip(1000).Take(100) in pure SQL?
...
(SELECT a,b,c, ROW_NUMBER() OVER (ORDER BY ...) as row_number
FROM Table) t0
WHERE to.row_number BETWEEN 1000 and 1100;
This works, but the need to manufacture the row_number from the ORDER BY may result in your query being sorted on the server side and cause performance problems. Even ...