[Java] Calendar Date to Timestamp

In Java you can convert a Date to a Timestamp simply by:

Date date = Calendar.getInstance().getTime();

This will return the current date, then:

Timestamp timestamp = new Timestamp(date.getTime());

where date.getTime() will return a long.

[Java] Format date with locale

In Java, you may need to format a date using a particular pattern or locale. You can easily do it with SimpleDateFormat:

SimpleDateFormat sdf = new SimpleDateFormat(pattern, locale);

Date date = Calendar.getInstance().getTime();

sdf.format(date); 

This code formats the current date using the given pattern and locale.

[SQL] Select column, max(count(column))

In SQL, to know which row id has the MAX(COUNT(*)) in a table, you would like to:

SELECT id, MAX(COUNT(*))

FROM table

WHERE [conditions]

But this will not work on its own, instead you should:

Excel spreadsheet functions - Funzioni foglio di calcolo

When working with Microsoft Excel, you will find the need to use spreadsheet functions sooner or later. Those functions can be put directly into a cell and do not require any knowledge of Basic.

However, their names are translated into the application language so non English copies will have localized function names; this means you will need to translate them into your locale before being able to use them otherwise you will get the error #NAME?

Remember that this operation is not necessary in order to view Excel files as upon opening they will automatically be converted to work with the application locale.

Here is a descriptive list of Excel 2003 functions.

Here you can translate function names between different languages.

Note: the same applies to OpenOffice.org / LibreOffice Calc

[SQL] Oracle LIMIT clause

To limit the number of rows returned by a query, in standard SQL you would:

SELECT *

FROM table

WHERE [conditions]

LIMIT number

In Oracle you just add ROWNUM to the WHERE clause like:

SELECT *

FROM table

WHERE [conditions] AND ROWNUM=1

To have the equivalent of SQL "LIMIT 1"

[PL/SQL] Test a string for a numeric value

In PL/SQL, you can easily check whether a string contains numeric values with:

LENGTH(TRIM(TRANSLATE(string, '0123456789', ' ')))

This will return null if the string contains only numeric characters otherwise it will return the number of non-numeric characters in it.

[How to] Run multiple Firefox instances

If you'd like to run multiple Firefox instances on Windows without having to fiddle with the profile settings and maybe run different versions too, you can always install both Firefox and Firefox portable (no need to have the same version).

Simply browse to the Firefox portable installation directory and edit the FirefoxPortable.ini file changing AllowMultipleInstances=false to AllowMultipleInstances=true

That's it, you can now run the two browsers side by side.