If you’re getting an error that reads “function array_sample(integer, integer) does not exist” when using the array_sample() function in PostgreSQL, it’s probably because your first argument is not an array. In particular, this specific error message implies that the first argument is an integer.
The first argument for this function must be an array.
To fix this error, be sure that your first argument to array_sample() is an array, not an integer.
MySQL 8.0.30 introduced generated invisible primary keys (GIPKs), which are primary keys that are automatically created whenever we create a table without explicitly defining a primary key.
GIPKs only work with the InnoDB storage engine, and they only work when we have GIPKs enabled.
In this article, I check whether or not GIPKs are enabled on my system, I then enable GIPKs, and finally I create a table with a GIPK.
Continue readingIn 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.
When we create a scheduled event in MySQL we have the option of using the COMMENT clause to add a comment to the event. Comments can be a handy addition that help explain what the event does, why it was created, etc.
So it’s probably quite rare that we would want to remove the comment from an event. But in the event that we do (pun intended!), we can simply update the event with a blank comment.
Continue readingPostgreSQL 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.
In MySQL we can create scheduled events, which are basically tasks that run according to a specified schedule.
We create scheduled events with the CREATE EVENT statement.
When we do this, we specify the schedule as well as the task to run.
Continue readingPostgreSQL 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.
In MySQL we can create scheduled events, which are tasks that run according to a specified schedule.
At any given time we can get a list of events for a given schema by using either of the following methods.
Continue readingSQLite’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.
In MySQL scheduled events are tasks that run according to a given schedule. After creating a scheduled event, we can modify it using the ALTER EVENT statement. This statement allows us to change the event’s definition, change its schedule, enable/disable it, rename it, and more. It also allows us to move the event to another database.
To move an event to another database, we use the ALTER EVENT statement with the RENAME clause, prefixing the event name with the database name (using dot notation).