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Working with Lists

A list is an ordered collection of zero or more VARCHAR values.

Actions

Construct

SPLIT(string)

Accessing

list[index]

Testing

ANY

value <operator> ANY(column)

The ANY function is used to apply a filter to each item in an array, and returns True if any item in the array matches the condition.

SELECT * 
  FROM $astronauts
 WHERE 'Apollo 11' = ANY(missions);

ANY supports the following operators: =, !=, >, <, >=, and <=.

ALL

value <operator> ALL(column)

The ALL function is used to apply a filter to each item in an array, and returns True if all items in the array matches the condition.

Note

ALL currently supports a subset of operators: =, !=.

SELECT *
  FROM $astronauts
 WHERE Search(missions, 'Apollo 11')

IN

The IN operator allows a column to be tested against a list of values.

SELECT *
  FROM $planets
 WHERE name IN ('Earth', 'Mars')

IN UNNEST

The combination of IN UNNEST allows a value to be tested for containment in a column.

SELECT *
  FROM $astronauts
 WHERE 'Apollo 11' IN UNNEST(missions)

Transforms

SORT

Converting Lists to Relations

Using UNNEST

UNNEST allows you to create a single column table either as a list of literals, or from a column of LIST type in a dataset.

SELECT * 
  FROM UNNEST((True, False)) AS Booleans;

Limitations

Lists have the following limitations

  • Statements cannot ORDER BY a list column
  • Statements cannot contain DISTINCT and JOIN when the relations include list columns
  • Lists cannot be used in comparisons

Note

Some restrictions may be resolved by the query optimizer, for example, Projection Pushdown may remove list columns as part of optimization. However, you should not rely on the optimizer to take any particular action.