NAMED_STRUCT

Description

The named_struct function is used to create a struct with specified field names and corresponding field values. This function can combine multiple fields and their values into a whole, making it convenient to display data in a structured form in query results.

Syntax Format

named_struct(f1, v1, f2, v2, ..., fN, vN)

Parameter Description

• f1, f2, ..., fN: Field names, type is string, representing the names of each field in the struct.
• v1, v2, ..., vN: Field values, types are T1, T2, ..., TN, representing the values corresponding to each field in the struct.

Return Type

• Returns a struct containing fields such as f1:T1, f2:T2, ..., fN:TN.

Usage Example

Example 1: Creating a simple named struct

SELECT named_struct('id', 1, 'name', 'Alice');

Return Results:

{"id":1,"name":"Alice"}

Example 2: Creating Complex Structures with Other Functions

SELECT named_struct('user', named_struct('id', 1, 'name', 'Alice'), 'created_time', '2022-01-01 10:00:00');

Return Results:

{"user":{"id":1,"name":"Alice"},"created_time":"2022-01-01 10:00:00"}

Example 3: Using Named Structs in Queries

SELECT id, named_struct('name', name, 'age', age) AS user_info
FROM users;

Assume the users table contains the fields id, name, and age, and the return result is:

id | user_info
--- | ---------------------------------------------------------------------------------
1  | {"name":"Alice","age":30}
2  | {"name":"Bob","age":25}
...

Notes

• Please ensure that the values of the field names f1, f2, ..., fN are valid strings, otherwise it may cause the function to fail.
• When field names conflict with existing field names, you need to use aliases or other methods to avoid conflicts.
• When using the named_struct function, please pay attention to the matching of field value types with the field types in the structure to ensure data correctness.