Database Management Systems
In MySQL, the PI() function returns the value of π (pi). The number π is a mathematical constant approximately equal to 3.14159 (although it can also be displayed with much greater precision than this).
The PI() function displays π with a default precision of 7 (i.e. 3.141593), however MySQL uses the full double-precision value internally.
In MySQL, the RAND() function allows you to generate a random number. Specifically, the function returns a random floating-point value v in the range 0 <= v < 1.0.
You can also influence the random number by providing a seed value as an argument.
In MySQL, the ROUND() function allows you to round a number up or down to a given number of decimal places.
The way it works is, you provide the number as an argument, and you have the option of choosing how many decimal places to round the number to. If you don’t specify the number of decimal places, the result will have no decimal places.
In MySQL, the CEILING() function allows you to round a number up to the nearest integer. More specifically, it returns the smallest integer not less than its argument.
You can also use the CEIL() function, which is a synonym for CEILING().
In MySQL, the FLOOR() function allows you to round a number down to the nearest integer. More specifically, it returns the largest integer not larger than its argument.
In MySQL, the JSON_LENGTH() function returns the length of a JSON document.
When you call this function, you provide the JSON document as an argument. You can also provide a path argument to return the length of a value within the document.
In MySQL, the JSON_DEPTH() function returns the maximum depth of a JSON document.
When you call this function, you provide the JSON document as an argument.
In MySQL, the JSON_TYPE() function returns the type of a JSON value. More specifically, it returns a utf8mb4 string indicating the value’s type.
You provide the JSON value as an argument.
In MySQL, the JSON_STORAGE_FREE() function shows how much storage space was freed up after a JSON Document was updated.
For a JSON column value, it shows how much storage space was freed in its binary representation after it was updated in place using JSON_SET(), JSON_REPLACE(), or JSON_REMOVE().
For a JSON document (or a string which can be parsed as one), this function returns 0.
In MySQL, the JSON_STORAGE_SIZE() function returns the number of bytes used to store the binary representation of a JSON document.
You provide the JSON document as an argument.
When the argument is a JSON column, this function returns the space used to store the JSON document as it was inserted into the column, prior to any partial updates that may have been performed on it afterwards.
When the argument is a string, the function returns the amount of storage space in the JSON binary representation that is created by parsing the string as JSON and converting it to binary.