Using the FROM clause - Cloud - 8.0

The FROM clause should be structured as follows:

FROM expression  

FROM expression AS alias     

When using a FROM clause without an alias, all identifiers used in the query are treated as relative to the identifier in the FROM clause, except when it is followed by an UNNEST clause or when the identifier is an absolute path. For example, in the following query:

FROM customers
SELECT {
	name,
	id
}

The elements selected are customers.name and customers.id. You would get the same result with this query, where the input data is named input:

FROM customers
SELECT {
	input.customers.name,
	input.customers.id
}

The INDEX keyword allows you to store the index of the current iteration in a variable. The variable must start with the $ character and cannot be a hierarchical identifier, for example, $item.index is not a valid variable. The variable must be unique throughout the query. The INDEX should be defined as follows:

FROM expression INDEX $variable_name       

The following examples are valid FROM clauses:

FROM customers AS c INDEX $i

FROM 1 TO 5 AS i

FROM toArray(address_1, address_2, address_3) AS addr INDEX $i

FROM ['a', 'e', 'i', 'o', 'u', 'y' ] AS vowels