Struct

STRUCT

A STRUCT is a dictionary of key-value pairs where keys are of type STRING. STRUCT is a fixed-size data type so values with the same STRUCT type must contain the same set of keys. User can think of a STRUCT column as a nested single column over multiple other columns.

Data Type	DDL definition
STRUCT	STRUCT(a INT64, b INT64)

Note: Updating STRUCT with update statement is not yet supported.

STRUCT creation

RETURN {first:'Xiyang', last:'Feng'};

Output:

-------------------------------
| STRUCT_PACK(Xiyang,Feng)    |
-------------------------------
| {FIRST: Xiyang, LAST: Feng} |
-------------------------------

STRUCT extraction

WITH {first:'Xiyang', last:'Feng'} AS fullName
RETURN fullName.first AS firstName;

Output:

-------------
| firstName |
-------------
| Xiyang    |
-------------

Alternatively you can use struct_extract() function

WITH {first:'Xiyang', last:'Feng'} AS fullName
RETURN struct_extract(fullName, 'first') AS firstName;