The correct answer is C. Casts the value from a VARIANT to a specified data type .
In Snowflake, the :: operator is the cast operator. It converts a value from one data type to another. When working with semi-structured data, it is commonly used to cast values extracted from a VARIANT column into standard SQL data types such as STRING, NUMBER, BOOLEAN, or TIMESTAMP.
Why C is correct:
A VARIANT value often needs to be explicitly cast before it is used in comparisons, calculations, or formatted output.
Example:
SELECT src:customer_id::NUMBER,
src:name::STRING
FROM my_table;
In this example:
src:customer_id::NUMBER
extracts customer_id from a VARIANT column and casts it to NUMBER.
Why the other options are incorrect:
A). :: does not specifically convert every VARIANT into an object. It casts to whichever data type is specified.
B). Extracting a value from a VARIANT uses path notation or functions such as GET and GET_PATH; ::
performs casting.
D). :: has nothing to do with random sampling.
Official Snowflake documentation reference:
Snowflake documentation describes :: as the cast operator and shows its use for converting semi-structured VARIANT values to explicit SQL data types.
Reference: Snowflake Documentation - Data type conversion; Snowflake Documentation - Cast operator; Snowflake Documentation - Querying semi-structured data; SnowPro Core Study Guide - Working with Semi-Structured Data.