In PostgreSQL, factorial() is a mathematical function that returns the factorial of a given integer. We pass the integer (it accepts bigint), and it returns the factorial as a numeric value.
In mathematics, the factorial is the product of all positive integers less than or equal to a given positive integer. It’s denoted by that integer and an exclamation point.
Continue readingIn PostgreSQL, we can use the || operator to concatenate two arrays. We can also use it to append or prepend a (compatible) non-array value to an array.
PostgreSQL offers a handy feature called domains that can greatly enhance data integrity and simplify database design. In this article, we’ll explore what domains are, how they work, and when to use them in our database projects.
Continue readingPostgreSQL allows us to create arrays and store them in the database as an array type. We can then go back later and update those arrays as required.
We can either replace the whole array, append or prepend elements, or update individual elements within the array. When we update individual elements, we can update one element or a whole slice. Below are examples of updating an array in PostgreSQL.
Continue readingIf you’re trying to use either lpad() or rpad() to pad a string in PostgreSQL but it’s just not working, maybe it’s because of the reasons listed below.
Fortunately this issue has a simple fix, and it can be resolved within seconds.
Continue readingIn PostgreSQL, the md5() function computes the MD5 hash of the specific text, and outputs the result in hexadecimal.
We pass the text as an argument when calling the function.
Continue readingNothing pulls me out of the “zone” quicker than attempting to drop a table, only to be told “Nope, that table has a dependency!”.
Granted, this usually only happens in my development environments, as I rarely have any need to drop tables in a production environment.
And that’s probably why it “pulls me out of the zone”. I suddenly have to stop and start thinking about what tables contain foreign keys to the one I’m trying to drop. In dev environments, we’re often trying things out and so it’s not out of the question that we might inadvertently try to drop a table without realising it has dependent objects.
Fortunately, when we’re working with PostgreSQL, we have a quick and easy method to overcome this barrier.
Continue readingPostgreSQL sometimes provides us with multiple functions that basically do the same thing. Such is the case with the following two functions that return the position of a given substring within a string.
Continue readingIn PostgreSQL, we can use the to_hex() function to convert a number to its equivalent hexadecimal representation.
The function accepts the number as an integer or bigint, and it returns the result as a text representation of its hexadecimal equivalent.
Continue readingBy default, PostgreSQL arrays are one-based. This means that we need to use 1 if we want to reference the first element in the array, 2 for the second, and so on.
But we also have the option of specifying our own subscript range for an an array. For example we could create a zero-based array, a ten-based array, or even a negative value such as a negative ten-based array.
We can do this by using subscripted assignment to specify the actual subscript range for the array. Basically, we prefix the array with the subscript range, enclosed in square brackets, and an equals sign (=) between it and the array.