BSON_MERGE

Syntax

BSON_MERGE(<obj1>, <obj2>)

Argument

<obj1>, <obj2>: A BSON object or an expression that evaluates to a valid BSON object.

Return Type

A BSON object.

Remarks

If the BSON objects include fields with identical names, the resulting object has the value corresponding to the last merged object for each respective field.
If the input is SQL NULL, BSON null or BSON undefined, it is considered equivalent to an empty object ({}).

Examples

Note: The following examples explicitly cast string to BSON for clarity. Similarly, the output is cast to JSON.

SQL

SELECT BSON_MERGE(NULL, '{"a":1, "b":2}':>BSON):>JSON AS Result;

+---------------+
| Result        |
+---------------+
| {"a":1,"b":2} |
+---------------+

SQL

SELECT BSON_MERGE('{"a":1,"b":{"c":1}}':>BSON, '{"c":2,"d":{"e":1}}':>BSON):>JSON AS Result;

+---------------------------------------+
| Result                                |
+---------------------------------------+
| {"a":1,"b":{"c":1},"c":2,"d":{"e":1}} |
+---------------------------------------+

SQL

SELECT BSON_MERGE('{"a":2, "b":2}':>BSON, '{"a": 3, "b":null, "c":3}':>BSON):>JSON AS Result;

+------------------------+
| Result                 |
+------------------------+
| {"a":3,"b":null,"c":3} |
+------------------------+