PostgreSQL array_to_string() Function

The PostgreSQL array_to_string() function concatenates all elements in an array with a delimiter and returns the result.

array_to_string() Syntax

Here is the syntax of the PostgreSQL array_to_string() function:

array_to_string(array, delimiter[, null_string]) -> text

Parameters

array

Required. array.

delimiter

Required. delimiter.

null_string

Optional. The string to replace the NULL entries .

Return value

The PostgreSQL array_to_string() function returns a string that is the result of concatenating all elements in an array using a delimiter.

The array_to_string() function will return NULL if the specified array is NULL.

array_to_string() Examples

This example shows how to use the PostgreSQL array_to_string() function to convert {1, NULL, 2, 1} to a comma-separated string.

SELECT array_to_string(ARRAY[1, NULL, 2, 1], ',');

 array_to_string
-----------------
 1,2,1

Note that the NULL element in the array is ignored. If you want to output the NULL element as a specific value, for example 0, use the following statement:

SELECT array_to_string(ARRAY[1, NULL, 2, 1], ',', '0');

 array_to_string
-----------------
 1,0,2,1

Now, we see that in the returned string, the NULL elements output 0.