Array constructor functions

An array constructor function constructs an array object. OceanBase Database supports the array() array constructor function and the [] operator.

array()

The array() function constructs an array object. The syntax is as follows:

array(elem1, elem2, elem3, ..., elemN)
[elem1, elem2, elem3, ..., elemN]

elem1 to elmenN: The input arguments must be of the same data type. For more information about supported array data types, see Overview of array data types.

Here is an example:

SELECT array(1, 2, 3);
+----------------+
| array(1, 2, 3) |
+----------------+
| [1,2,3]        |
+----------------+
1 row in set

rb_build

The rb_build() function is used to convert an array of integers into a RoaringBitmap. The syntax is as follows:

rb_build(arr)

The parameters are described as follows:

• arr: The type of the input parameter must be an array.

The return value is a RoaringBitmap that contains all the elements of the array.

The following constraints apply:

• The array cannot contain null elements.
• If the array is a nested array, the function recursively extracts the base elements of each subarray and inserts them into the RoaringBitmap.
• The RoaringBitmap supports the insertion of unsigned 64-bit integers (uint64) and signed 32-bit integers (int32). Similar to the behavior of rb_from_string, a negative signed 32-bit integer is first converted to an unsigned 32-bit integer before being inserted into the RoaringBitmap. Therefore, the allowed integer range is from the minimum value of signed 32-bit integers to the maximum value of unsigned 64-bit integers, that is, [INT32_MIN, UINT64_MAX].

Here is an example:

SELECT rb_to_string(rb_build([1.2]));
ERROR 5083 (22000): Invalid data type for the operation

SELECT rb_to_string(rb_build([0,1,2]));
+---------------------------------+
| rb_to_string(rb_build([0,1,2])) |
+---------------------------------+
| 0,1,2                           |
+---------------------------------+
1 row in set

SELECT rb_to_string(rb_build([[0,1],[2],[2,3]]));
+-------------------------------------------+
| rb_to_string(rb_build([[0,1],[2],[2,3]])) |
+-------------------------------------------+
| 0,1,2,3                                   |
+-------------------------------------------+
1 row in set

[]

You can also use the [] operator to construct an array object. Here is an example:

SELECT [1, 2, 3];
+-----------+
| [1, 2, 3] |
+-----------+
| [1,2,3]   |
+-----------+
1 row in set