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How do I get the last inserted ID of a MySQL table in PHP?
I have a table into which new data is frequently inserted. I need to get the very last ID of the table. How can I do this?
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How do I write LINQ's .Skip(1000).Take(100) in pure SQL?
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(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 ...
Applying a function to every row of a table using dplyr?
...o create an appropriately vectorised function.
R provide pmax which is suitable here, however it also provides Vectorize as a wrapper for mapply to allow you to create a vectorised arbitrary version of an arbitrary function.
library(dplyr)
# use base R pmax (vectorized in C)
iris %>% mutate(max...
When to use single quotes, double quotes, and backticks in MySQL
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Backticks are to be used for table and column identifiers, but are only necessary when the identifier is a MySQL reserved keyword, or when the identifier contains whitespace characters or characters beyond a limited set (see below) It is often recommende...
How to put more than 1000 values into an Oracle IN clause [duplicate]
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Put the values in a temporary table and then do a select where id in (select id from temptable)
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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...
How do I handle too long index names in a Ruby on Rails ActiveRecord migration?
...an unique index that gets created from the foreign keys of four associated tables:
9 Answers
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Finding duplicate values in a SQL table
...till requires all non-aggregated columns in the GROUP BY.
MySQL is unpredictable and you need sql_mode=only_full_group_by:
GROUP BY lname ORDER BY showing wrong results;
Which is the least expensive aggregate function in the absence of ANY() (see comments in accepted answer).
Oracle isn't mainstr...
What good are SQL Server schemas?
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Schemas logically group tables, procedures, views together. All employee-related objects in the employee schema, etc.
You can also give permissions to just one schema, so that users can only see the schema they have access to and nothing else.
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How to change height of grouped UITableView header?
I know how to change the height of the section headers in the table view. But I am unable to find any solution to change the default spacing before the first section.
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