In PostgreSQL we can use the random_normal() function to generate a normally-distributed random number.
A normally-distributed random number is a random variable with a Gaussian distribution. This is said to be normally distributed, and is referred to as a normal deviate.
In PostgreSQL we have the ability to create variable-length multidimensional arrays and define columns as array types.
Here’s a quick overview of PostgreSQL arrays.
PostgreSQL has an aggregate function called array_agg() that allows us to generate an array from the result set of a query.
The function accepts an argument which is used to generate the array. This argument is typically the column that we want to use in order to populate the array.
In PostgreSQL we can create arrays with the ARRAY constructor. An array constructor is an expression that builds an array value using values for its member elements.
PostgreSQL has a generate_subscripts() function that generates a series comprising the valid subscripts of a given array.
We pass the array to the function, along with the dimension that we want to use. We also have the option of returning the series in reverse order.
In PostgreSQL array_shuffle() is a system function that randomly shuffles the first dimension of a given array.
The array_shuffle() function was introduced in PostgreSQL 16, which was released on September 14th 2023.
In PostgreSQL array_sample() is a system function that returns an array of a specified number of items randomly selected from the given array.
The array_sample() function was introduced in PostgreSQL 16, which was released on September 14th 2023.
PostgreSQL 16 introduced the date_subtract() function that allows us to subtract an interval from a timestamp with time zone.
It computes times of day and daylight-savings adjustments according to the time zone named by the third argument, or the current TimeZone setting if that is omitted.
PostgreSQL 16 introduced the date_add() function that allows us to add an interval to a timestamp with time zone.
It computes times of day and daylight-savings adjustments according to the time zone named by the third argument, or the current TimeZone setting if that is omitted.
SQLite’s json_valid() function allows us to check whether a JSON string is well formed or not.
Prior to SQLite 3.45.0 the json_valid() function only accepts one argument – the value to check. However, from SQLite 3.45.0 (released on 15 January 2024), we can now provide an optional second argument to define what valid – or “well formed” – means.