In PostgreSQL, you can use the OVERLAPS operator to test for overlapping time periods.
The function returns true when two time periods (defined by their endpoints) overlap, and false when they do not overlap.
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How to Format Numbers as Currency in PostgreSQL
To format a number as currency in Postgres, you can either convert it to the money data type, or use to_char() to convert it to text that includes the appropriate currency symbol.
This obviously assumes that the number isn’t already stored using the money type.
Below are examples of each of these options.
Continue readingHow to Pause the Execution of a Statement in PostgreSQL
PostgreSQL includes three functions that allow you to delay the execution of the server process. the execution of a statement.
In other words, you can run a statement and have it pause half way through, before continuing on its merry way.
The three functions are:
These are all very similar, but they work in slightly different ways.
Below are examples of each one.
Continue readingFormat the Month in Roman Numerals in PostgreSQL
In PostgreSQL, you can use the to_char() function to return dates in various formats.
One of the things you can do with this function is return the month portion of a date in roman numerals.
Continue readingHow to Set the Interval Output Format in PostgreSQL
When working with the interval data type in PostgreSQL, you can change the way the interval output is formatted.
You have a choice of four formats that your intervals can be output in.
Continue readingCalculate the Age in Years in PostgreSQL
Postgres has the age() function that returns the age in years, months, and days based on two dates.
This works fine unless you only want to return the age in years.
For example, you simply want to return a person’s age based on their birthday. You want something like 32 instead of 32 years 4 mons 67 days, which is what age() is likely to return.
Fortunately there’s an easy way to do this in PostgreSQL.
Continue readingGet the Week Number from a Date in PostgreSQL
In PostgreSQL you can use the extract() function to get the week number from a date.
You can also use the date_part() function to do the same thing.
Get the Short Day Name in PostgreSQL
In PostgreSQL, you can use the to_char() function to get the short day name from a date.
By “short day name” I mean the abbreviated day name, for example Fri, Mon, etc.
The to_char() function accepts two parameters; the date and the format string with which to format that date.
Get the Day from a Date in PostgreSQL
In PostgreSQL you can use the extract() function to get the day from a date.
You can also use date_part() to do the same thing.
When extracting the day from a date, you need to specify what sense of the word “day” you mean. For example, “day of week”, “day of month”, “day of year”, etc.
Convert a Julian Day to a Date in PostgreSQL
Here are two ways to convert a given Julian day to its date value in PostgreSQL.
The first method directly inputs the Julian day into the date data type.
The second method uses the to_date() function to return the same result.
Julian day is the number of days since Monday, January 1, 4713 BC using the proleptic Julian calendar, which is November 24, 4714 BC, in the proleptic Gregorian calendar.
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