The `UNNEST()` function in Snowflake is used to transform an array of values into a table format. It takes an array as input and returns a table with one row for each element of the array.
Here is an example of how to use the `UNNEST()` function:
“`
SELECT *
FROM TABLE(UNNEST(ARRAY_CONSTRUCT(‘apple’, ‘banana’, ‘cherry’))) AS fruits;
“`
This will produce a table with three rows, one for each element of the array: `apple`, `banana`, and `cherry`.
You can also use the `UNNEST()` function with nested arrays to produce a table with multiple columns. For example:
“`
SELECT *
FROM TABLE(UNNEST(ARRAY_CONSTRUCT(ARRAY_CONSTRUCT(‘apple’, ‘red’),
ARRAY_CONSTRUCT(‘banana’, ‘yellow’),
ARRAY_CONSTRUCT(‘cherry’, ‘red’))))
AS fruits(name, color);
“`
This will produce a table with two columns (`name` and `color`) and three rows. The `name` column will contain the fruit name (`apple`, `banana`, or `cherry`) and the `color` column will contain the fruit color (`red` or `yellow`).
Overall, the `UNNEST()` function is a powerful tool in Snowflake for transforming arrays into a table format, which can be useful for further analysis and processing of data. The unnest() function is an important feature in Snowflake because it allows users to easily work with complex data structures such as arrays and objects. It enables you to transform a multi-valued column into multiple rows, making it easier to query and analyze the data.
