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array_cat

1. ARRAY_CAT Function​

The ARRAY_CAT function in H2 database is used to concatenate two or more arrays into a single array.

2. Syntax​

The syntax for the ARRAY_CAT function in H2 database is as follows:

ARRAY_CAT(array1, array2, ...)

Arguments​

  • array1, array2, ...: The arrays to be concatenated. Each argument should be an array.

Return​

  • The ARRAY_CAT function returns a new array that is the concatenation of the input arrays.

3. Notes​

  • The ARRAY_CAT function in H2 database concatenates the arrays in the order they are provided as arguments.
  • If any of the input arrays is NULL, the resulting array will also be NULL.
  • The input arrays should have elements of the same type. If the element types differ, you may need to convert them using appropriate functions like CAST or CONVERT.
  • The ARRAY_CAT function does not modify the original arrays; it creates a new array as the result.

4. Examples​

Here are a few examples demonstrating the usage of the ARRAY_CAT function in H2 database:

Example 1 - Concatenating two arrays:​

SELECT ARRAY_CAT(ARRAY[1, 2, 3], ARRAY[4, 5, 6]) AS concatenated_array;

Output:

concatenated_array
------------------
[1, 2, 3, 4, 5, 6]

Example 2 - Concatenating three arrays:​

SELECT ARRAY_CAT(ARRAY['apple', 'banana'], ARRAY['cherry'], ARRAY['date']) AS concatenated_array;

Output:

concatenated_array
------------------
[apple, banana, cherry, date]

Example 3 - Concatenating arrays stored in columns:​

CREATE TABLE arrays (
  id INT PRIMARY KEY,
  array1 INT[],
  array2 INT[]
);

INSERT INTO arrays VALUES (1, ARRAY[1, 2], ARRAY[3, 4]);

SELECT id, ARRAY_CAT(array1, array2) AS concatenated_array
FROM arrays;

Output:

id | concatenated_array
---+-------------------
1  | [1, 2, 3, 4]
  • array_append - Append an element to an array
  • ARRAY_PREPEND - Prepend an element to an array
  • ARRAY_CONCAT - Concatenate multiple arrays into a single array