Fix “function array_sample(integer, integer) does not exist” in PostgreSQL

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.

Continue reading

How to Return Elements from a JSON Array in MariaDB

MariaDB includes two selectors that enable us to select elements from JSON arrays:

  • [N] selects element number N in the array (for example, [0] to select the first element).
  • [*] selects all elements in the array.

These can be used in a number of JSON functions that are included in MariaDB. The following examples use them with the JSON_EXTRACT() function in order to return selected array elements.

Continue reading