Database Management Systems
Ever since version 10.3.1, MariaDB has included both a LENGTH() function and a LENGTHB() function.
That second one has a B at the end of the name. So it’s kind of like Length A and Length B, except that Length A doesn’t have the A.
Confused?
I was, when I first encountered LENGTHB(). I already knew about LENGTH(), so why the need for a “B” version?
Let’s find out.
Continue readingIn Oracle, the SOUNDEX() function returns a character string containing the phonetic representation of its argument. This is known as the Soundex string.
Soundex is a phonetic algorithm for indexing names by sound, as pronounced in English. If two words sound the same, they should have the same Soundex string. If two words sound similar, but not exactly the same, their Soundex string might look similar but not exactly the same.
The function accepts one argument: the string for which to return the Soundex string from.
Continue readingIn Oracle, the SUBSTR() function returns a substring from a given string.
SUBSTR() requires at least two arguments; the string, and the position for which to extract the substring from. It also accepts an optional third argument that allows you to specify how long the substring should be.
SUBSTR() can also be thought of as a group of functions. There are five separate functions; SUBSTR(), SUBSTRB(), SUBSTRC(), SUBSTR2(), and SUBSTR4(). Each function calculates the length in a different way.
In MongoDB, the $unionWith aggregation pipeline stage performs a union of two collections, and it includes duplicates.
This behaves in a similar way to SQL’s UNION ALL, which also includes duplicates. By contrast, using just UNION (i.e. without the ALL)in SQL removes duplicates.
In MongoDB, we don’t have the option of specifying $unionWith ALL or similar, so we need to reduce duplicates in another way.
In MongoDB, we can remove duplicates by using the $group stage.
In Oracle, the CONCAT() function performs a string concatenation on its arguments. It returns the string that results from concatenating its arguments.
Concatenation is the operation of joining multiple strings end-to-end.
Continue readingIn Oracle, the WIDTH_BUCKET() function allows you to construct equiwidth histograms, in which the histogram range is divided into intervals that have identical size.
For a given expression, WIDTH_BUCKET() returns the bucket number into which the value of this expression would fall after being evaluated.
Below is a list of the JSON functions available in MariaDB.
Continue readingIn Oracle Database, the TRUNC(number) function returns a given number, truncated to a given number of decimal places.
Oracle also has a TRUNC(date) function, which is used on dates. This article is solely about the TRUNC(number) function, which is used on numbers.
In Oracle, the SIGN() function returns the sign of its argument as -1, 0, or 1, depending on whether the argument is negative, zero, or positive, and also depending on whether the argument is of type NUMBER or a floating-point number.
You can use the SWITCHOFFSET() function in SQL Server to change the time zone offset on a datetimeoffset value.
The function accepts two arguments; a datetimeoffset(n) value (or an expression that can be resolved to a datetimeoffset(n) value), and the new time zone.
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