STRUCT_INSERT

Dexcription

The struct_insert function is used to insert a new field into a structure (struct). The name of the new field is specified by the name parameter, and its value is specified by the expr parameter. The optional indexToInsert parameter is used to specify the insertion position. If indexToInsert is not specified or its value is 0, the new field will be inserted at the end of the structure. If indexToInsert is 1, the new field will be inserted after the first field, and so on.

Functionality

• Add a new field to the structure.
• Control the insertion position of the new field through the indexToInsert parameter.

Parameters

• struct: The structure into which the new field needs to be inserted.
• name: The name of the new field, must be a string constant.
• expr: The value of the new field, can be data of any type.
• indexToInsert: (Optional) Specifies the insertion position of the new field, an integer constant, default value is 0.

Return Result

Returns a new structure, the structure of which depends on the inserted key-value pair and the specified insertion position.

Usage Example

1. Add a new field to the end of the structure:

SELECT struct_insert(named_struct('a', 1, 'b', 2), 'x', 'hello');
-- Result: {"a":1, "b": 2, "x":"hello"}

2. Insert new fields at the beginning of the struct:

SELECT struct_insert(named_struct('a', 1, 'b', 2), 'x', 'hello', 0);
-- Result: {"x":"hello", "a":1, "b": 2}

3. Insert a new field after the first field:

   SELECT struct_insert(named_struct('a', 1, 'b', 2), 'x', 'hello', 1);
   -- Result: {"a":1, "x":"hello", "b": 2}

4. Insert a new field before the second field:

SELECT struct_insert(named_struct('a', 1, 'b', 2), 'y', 3, 2);
-- Result: {"a":1, "y":3, "b": 2, "x": "hello"}

5. Insert new fields into a structure that contains nested structures:

SELECT struct_insert(named_struct('outer', named_struct('inner', 'value')), 'newField', 'newValue');
-- Result: {"outer":{"inner":{"value"},"newField":"newValue"}}

Notes

• Please ensure the name parameter is a string constant, otherwise it may cause the function to fail.
• The valid range for the indexToInsert parameter is from 0 to the number of struct fields (inclusive). Values outside this range will cause the function to fail.
• When the insertion position conflicts with existing fields (for example, attempting to insert a new field at the position of an existing field), the function will return an error.